On a divine astral plane populated by eternal beings called celestials, one stood out with magic beyond compare. The others feared this individual's strength and split them into two separate beings, casting the halves to opposite ends of the cosmos.
But the two halves, the Sundrop and Moonstone, found each other again. Rather than recombining, they fell in love. And instead of wielding the great power they had as one being, their magic worked together through their love and commitment to the other. The Sundrop on her own held the power of life, healing, light, energy, and organics; the Moonstone on her own held the power of death, decay, darkness, matter, and inorganics; and together, they were again able to do anything.
They did not seek control over others. They merely wished to live in harmony with the rest of their home, enjoying the love they shared. But the other celestials, again afraid of their power being together, did a trick to cast the Sundrop and Moonstone out and bind them to a mortal plane in the form of a flower and rock, far apart from each other.
The Sundrop and Moonstone could not move - they were stuck where they landed. But the Sundrop could send out roots and the Moonstone could send out spikes of black rock and for years they searched for each other under the earth until they found each other in the middle, the roots holding onto the rocks like holding hands so they could be together again. And they stayed like that for millenia, clinging to each other deep underground, until the Sundrop was suddenly ripped from the earth.
The Moonstone knows immediately that the Sundrop is gone - their physical contact with each other had maintained a psychic connection that was abruptly severed. The Moonstone, outraged, sends out black rocks in search of her wife.
The Sundrop and Moonstone depend on each other to be their best selves. Without the Moonstone, the Sundrop's ability to create boundaries disappears. She wants to help people, and will do so even if it destroys her. So when she is torn from the earth, sensing the urgency and grief of the guards around her, she does not fight back. She allows herself to be turned into an elixir and given to the ailing queen, and she is reborn without memories fused with a human child. The king and queen's daughter is a hybrid: both human and celestial.
The princess Rapunzel is stolen away nearly immediately by the woman who wishes to abuse her powers of restoration and regeneration. Rapunzel remains trapped for eighteen years as the Moonstone desperately continues to send out her black rock spikes in search of the Sundrop, ravaging landscapes between the Dark Kingdom and Corona.
Rapunzel is freed from her tower by a dashing rogue who learns how to care about others by bearing witness to her pure heartedness. He sacrifices his own life for her freedom, her captor is destroyed, and he is resurrected through a tear because Rapunzel's magic resides within her and not just in her hair. The two become best friends, he and the pub thugs who aided Rapunzel's escape are pardoned for their past crimes by the crown, and he is given lodgings in the castle in thanks for rescuing their princess.
A few months after Rapunzel is freed, her new friend and Lady-in-Waiting Cassandra discovers the black rocks that have just recently emerged where the Sundrop once grew. When she brings Rapunzel there, the Moonstone senses her presence. The rocks glow blue at Rapunzel's proximity and when she touches one, the Moonstone desperately attempts to restore their psychic link. Rapunzel's celestial half reacts in fear, not recognizing the Moonstone's magic, and the stones explode. The rush of foreign magic brings out her own, and her hair is restored.
Although the Moonstone could not reconnect to her wife, she had spent so long in fear of the Sundrop being harmed that at her touch the Moonstone completed a partial switch of their powers: the Moonstone granted Rapunzel invulnerability to keep her safe, allowing her also to access the decay spell. In return the Moonstone received Rapunzel's power of advanced regeneration and her ability to access the healing spell.
Despite the initial failure with reconnecting to her wife, the Moonstone refuses to give up. She senses the Sundrop's proximity still and sends black rock to try to reach her. Rapunzel and Cassandra flee in fear from the rapidly approaching spikes.
Even once her wife has escaped her range of sensing, the Moonstone knows she must be nearby, so she sends spikes to pierce the surface in Corona with more frequency and intensity.
Eventually, she again senses her wife against one of her spikes, and she tries to restore their connection. Rapunzel's dormant power reacts again to the unfamiliar magic, and the spikes explode. And again the Moonstone refuses to give up, and she gives chase.
Rapunzel had intended for the spikes to explode, to take out the masked men chasing her and her friends. She did not intend for the spikes to pursue her, trapping them in her tower and causing them to jump off of the roof to escape, with Rapunzel for the first time accessing her magic to move her hair to protect them. Rapunzel's tower collapses from the onslaught of black rocks, but their jump took Rapunzel out of the Moonstone's range of sensing, and the Moonstone is again forced to give up her chase.
The Moonstone recognizes that her plan has not been working so the next time she senses her wife, she does not immediately seek to restore their connection. When she feels the Sundrop against her, she waits to see what she wishes to do. Even without their psychic link the Moonstone can sense the Sundrop's fear of something around her, and the Moonstone sends spikes to destroy the threats.
Varian's automatons are speared by the rocks, leaving only his mecha. Rapunzel's hair had reacted on its own to the spikes around her, seeking the rocks as the roots of the original Sundrop flower would. The Moonstone extends more spikes carefully towards Rapunzel again, who grabs hold of them with her hands. Sensing the Moonstone through her direct contact, her power is further awakened and she sends out a shockwave to take out Varian's mecha.
Cassandra is thrown in the blast and struck by black rock shards that tear open her shoulder. While she heals - Rapunzel does not leave on her journey until Cassandra recovers - a tiny piece of black rock from the shrapnel of the explosion is embedded in her shoulder.
The Moonstone realizes that for whatever reason, she cannot connect to the Sundrop psychically, and the Sundrop is capable of moving. She sends black rocks to destroy the wall and point in the direction of the Dark Kingdom for the Sundrop to follow.
On Rapunzel's journey, when Rapunzel touches the black rocks nothing happens anymore. She can't control them or explode them, because the Moonstone no longer sends magic to her through the spikes - and the stones no longer glow blue in her presence - so she doesn't react to it. The Moonstone has a plan: leading the Sundrop to her. She doesn't need to do anything else.
Rapunzel learned from her father and documents retrieved in Varian's laboratory about a dark power responsible for the spikes, which only attacked Corona because her father uprooted the Sundrop that had protected them. Early in Rapunzel's journey she meets Adira, a researcher who tells Rapunzel that the dark power, the Moonstone, resides in an abandoned and ancient kingdom far to the east. She explains that she and her team had discovered the Moonstone decades ago, and since then she had been seeking its counterpart, a light power, that would cancel out the dark and protect the world from it. She tells Rapunzel that she is that light power, the Sundrop, and it is her destiny to reunite the two powers. And if she does not, the Moonstone would continue to send out its spikes in search of her until it has destroyed the world.
The Moonstone can vaguely feel Cassandra, especially when she touches one of the black rocks. This gives the Moonstone an idea: she knows that the Sundrop obtained some kind of form that freed her from being stuck in one location, and she thinks that she could get a form like that too. As the group's journey progresses Cassandra begins having dreams of the Dark Kingdom and the Moonstone's chamber that she can only vaguely remember when she wakes up.
When they approach the Great Tree, Adira shares that the others in her team had different ideas of how to go about managing the Moonstone that they uncovered. She and Quirin sought to find its light counterpart, while Hector and Edmund sought to keep anyone from ever finding it and unlocking control of its dark power. She warns that the closer they get to the Dark Kingdom, the more likely they'll encounter the two who stayed behind. Shortly after her warning they fight off Hector, who tries to kill them to keep them from completing their journey.
In the Great Tree Adira tells the group that it was once the lair of the evil sorcerer Zhan Tiri. They discover a room full of documents in the Tree, including ancient writings on the Sundrop and Moonstone. Rapunzel finds an incantation similar to her healing spell, and when she uses it she's overtaken by a dark spell of decay that she's only snapped out of when Adira pushes her into water.
Cassandra is becoming increasingly frustrated with Rapunzel. She always felt pushed aside and not given a chance in Corona, where her father refused to work towards changing Corona law to allow a woman - her - into the guard, despite her proficiency in weapons and law that exceeded most of his men. Even when he had been put out of commission when Varian kidnapped the queen, leaving the guards without a leader, he refused to recognize her as the most worthy replacement and chose one of his other guards. She only rarely got assignments from him for guard work and was told to continue working as a maid, orders that she followed out of fear of his old threat of sending her to a convent if she disobeyed him.
With Rapunzel, Cassandra had gotten used to a respect she never had before. For the first time in her life she was being listened to and made to feel important. Spending every day with the princess since a couple weeks after her liberation from the tower, Cassandra taught Rapunzel much about the castle, Corona, and the outside world in general. Rapunzel thought she was amazing, knowledgeable, and real, and she was delighted to have Cassandra as a guide and companion. She put a great deal of trust in Cassandra and even looked up to her, never considering her or treating her like the servant that her position dictated she was.
This changed as their journey went on. Rapunzel dismissed Cassandra's importance as her (unofficial) bodyguard, acted like Cassandra's excessive focus and planning for their journey to continue smoothly was an inconvenience rather than the only thing keeping them moving, and stopped listening to Cassandra's advisements on decisions for their journey. Worse still, she refused to acknowledge the change in her behavior, and when Cassandra finally confronted her in the Great Tree about how Rapunzel was being foolish for trusting Adira blindly, Rapunzel snapped orders at her to stop her from speaking. Even when Rapunzel felt some uncertain guilt afterwards she botched the apology, simply telling Cassandra that Cassandra will need to get used to them disagreeing, especially when Rapunzel becomes queen.
So Cassandra swallows her frustrations. Shortly after their argument and not-quite-reconciliation, Hector attacks the group again. The fight results in Hector getting possessed by the evil heart of the Tree - Zhan Tiri's magic. When Cassandra tells Rapunzel that she could defeat him if Rapunzel helps her escape from the vines, Rapunzel ignores her and uses the decay spell instead. The spell works in taking down the heart of the Tree, leading the rest of it to start collapsing. Rapunzel is frozen again from the spell and as the rest of their friends flee, Cassandra runs to Rapunzel and tries to shake her out of the trance so she could escape. Touching Rapunzel during the spell burns Cassandra's right arm up to her elbow with a terrible curse of decay: it becomes blackened, gnarled, the skin pulled taught against her bones and tendons, rendering it dramatically weakened. Rapunzel tries to help her but Cassandra refuses to let her look at it, hiding it in a glove and then under a suit of armor she finds scattered among the Tree's wreckage.
They spend three days trapped in the House of Yesterday's Tomorrows, at which time Zhan Tiri's servant attempts to trap Rapunzel in a dream world in order to drain her magic and set Zhan Tiri free. Rapunzel escapes, but not before her magic is used to allow Zhan Tiri to materialize as a phantom and show Cassandra the memory of her young childhood. With Rapunzel free, Zhan Tiri is again banished.
When the group finally arrives at the Dark Kingdom, they find a wasteland under low-hanging, ominous clouds that cast the entire landscape in shadow. There is no greenery around the ruins of a grand palace, perched on a cliff, only stark stone and huge spikes of black rock. The wind that blows towards them from the wasteland is cold.
A man with black armor, hood made from a bear's head, and an enormous axe tries to keep the group from getting to the palace. After their fight, Adira speaks to the man - Edmund - and convinces him that they have the power of light that could finally stop the Moonstone. Rapunzel's hair glows with their proximity to the palace, and at the sight Edmund relents, knowing that even if their plan did not work at least they were not there to use the power for evil.
Cassandra's had a strong sense of déjà vu since they first laid eyes on the Dark Kingdom in the distance, but as they approach the palace it becomes overwhelming. She's not said anything to her companions, caught somewhere between not thinking it important and not trusting them. When Edmund tells the group that they'll need to find a roundabout way into the palace because more black rock has appeared to prevent them from going through the front gate, Cassandra ignores him and approaches the black rock doors. Without thinking she removes the gauntlet on her left hand, pushing her knife into the skin to release blood that she presses to the stone. The doors immediately glow blue and recede.
Everyone else in the group is severely alarmed by this, but Cassandra behaves as though she doesn't even register anything out of the ordinary. Entering the palace she finally admits to Rapunzel that she feels like she's done all of this before.
It's only a minute later that Cassandra stops and tells Rapunzel that she has done all of this before.
She turns to Rapunzel and says, "This isn't about you… It was never about you. This is my destiny. The Moonstone chose ME." Before Rapunzel can respond, Cassandra turns and takes off down the corridor, spikes of black rock turning blue and receding in front of her to let her pass. The spikes reappear behind her, so even as Rapunzel runs after her she cannot catch up.
When Rapunzel reaches the Moonstone chamber, Cassandra is standing in front of its pedestal. Rapunzel tries to call out to her, and Cassandra draws her sword and points it at Rapunzel while angrily telling her of all her grievances: Rapunzel casting her aside, no one appreciating her or giving her a chance, Gothel's abandonment of her, how she's always been kept powerless, Rapunzel being condescending and a bad friend, to name a few. She says again that the Moonstone chose her and that taking it is her destiny. Rapunzel tries to answer her but Cassandra turns and grabs the Moonstone, releasing a huge blast of energy that knocks Rapunzel to the ground.
The Moonstone is thrilled. Her time is at hand. She will finally be freed from her immovable state and have the ability to reconnect with her wife.
However, the Moonstone isn't as good with organics as the Sundrop is. And the Sundrop was reborn without memories, which is a dramatically different process than a young adult human and a spirit with many millennia of memories trying to fuse into one being.
The ground shakes and Rapunzel hears a terrible shattering all around her as every black rock in the chamber fractures into tiny pieces and showers to the ground. She pushes herself up to look towards the Moonstone's pedestal as the energy blast subsides, and she sees Cassandra collapsed in front of it, electric blue magic zapping off of her. Cassandra pushes herself up as Rapunzel did, and Rapunzel sees her hair has turned a bright blue and that the Moonstone is set under her left collarbone in a new armor of black rock. Rapunzel gets up just as Cassandra does, and she tries to call out to her friend to ask if she's okay.
But that is not Cassandra. The shattering of black rocks mirrored the shattering of Cassandra and the Moonstone's minds in their attempt to combine. The Moonstone-Cassandra hybrid standing in the chamber is left with all of her memories and sense of self - from both halves - in pieces. She does not understand what Rapunzel is saying to her, where she is, who Rapunzel is, nor who she is. A fleeting fragment passes through her mind, and she remembers how badly she wished to escape the chamber. She summons black rock to break an exit in the wall away from Rapunzel, and she takes off without saying a word.
The Moonstone-Cassandra hybrid (M-C) does not only flee the chamber, but also the wasteland of the Dark Kingdom. She reaches a forest and remains there for several months, only able to hold onto some memories or sense of self for brief periods before she loses them again. She tries desperately to figure out who she is and what she's doing. She's confused and misses her wife, except she's mad at her wife and also doesn't have a wife. Being able to perceive visuals is new and overwhelming except it's not, she wonders where her astral home is but that place doesn't make sense and this one does. Fragments of her memory try to build in her mind but none of them fit together and she falls to pieces again very easily. She doesn't eat or sleep anymore.
Meanwhile, Rapunzel and her friends are brought back to Corona with great urgency via airship to liberate the kingdom from the Saporians. Rapunzel re-befriends Varian and they rescue the kingdom. For months Rapunzel acts as interim queen and tries to help her parents recover their memories. She throws herself into her work to distract from how her best friend betrayed her, but when she lays down to go to sleep at night she can no longer occupy her thoughts with tasks, and she often falls asleep crying from her heartbreak.
The first time Rapunzel sees or hears from Cassandra again is when M-C shows up in Corona and tries to kill Frederic in the throne room during Eugene's birthday party.
In the wilderness, M-C had two thoughts at once that managed to stick firmly in her mind: her wife was taken, and the Coronan king dug up the special flower. The combination of these thoughts led her to Corona to get revenge on the king who took Flower Wife.
Rapunzel doesn't understand what's happening. M-C shows up in Corona after months of no contact to attack her father, snarling barely-coherently about how he took someone and that he's a monster. Rapunzel tries to lasso M-C and restrain her, and they begin to fight as people flee.
M-C doesn't recognize Rapunzel as Flower Wife. She actually doesn't remember anything about Flower Wife, only that she was really, really important. She decides to destroy the kingdom that took Flower Wife - Corona's crest becomes a trigger for her - and she throws Rapunzel away from her, knocking her out.
Rapunzel's friends carry her with them to flee as M-C begins summoning huge spikes of black rock to lay waste to the castle, and then the capital city surrounding it. Royal guards lead civilians to evacuate, and before long the citizens have all fled the city that has been ravaged entirely by spikes. As people fled they felt the air grow cold around them, and witnessed plants lining the windows and streets of the city wither with unnatural speed.
But M-C does not stop there. She leaves the island to begin wrecking the mainland as well, leaping with unnatural strength between giant spikes of black rock that she summons. Plants wilt and the air chills around her wherever she goes. Eventually every Coronan has either escaped the kingdom through the main gate of the wall or fled to Old Corona by the wall breach to evade the rampage. Rapunzel, with her family and friends in Old Corona, finally wakes up and is horrified.
M-C, seeing a lot of Corona, remembers more bits from her life as Cassandra. Besides the things that make her even more agitated, like a sense of no control in her life and a vague fear of being sent away, she remembers that the name of the important flower was the Sundrop. (She forgets it was her wife, though, and pretty much everything else.) Arriving at Old Corona, Rapunzel is ready to fight her again to defend her loved ones, but M-C stops her rampage and demands that they give her the Sundrop.
Rapunzel tells M-C that she can't do that because the Sundrop is literally inside of her. M-C, pacing and increasingly on edge, says that then she'll take Rapunzel.
But Rapunzel is acting queen now, and she knows she can't abandon her people. Rapunzel tries to get M-C to talk to her, but M-C doesn't have much to say on account of how she's already forgetting who all these people are and having random flares of anger from seeing Rapunzel, who she is mad at for a reason she doesn't remember. She says that if Rapunzel doesn't give her the Sundrop she won't stop at Corona, she'll start destroying the rest of the world too. Rapunzel, horrified by the threat, tells Eugene and the others to lead the rest of her people out of the breach in Corona's wall to take refuge in another kingdom, and that she'll stay with Cassandra in Corona. She thinks that she might be able to get through to Cassandra and have everything go back to normal.
M-C experiences one singular thought that isn't overwhelmed by anger: she has the vaguest memory of Rapunzel leading the Coronans during the ice storm and becomes certain that if Rapunzel isn't there to lead them, they would all die. The vague memory from her past carries a sense of responsibility that makes her not want that to happen to them, as she has already forgotten she just destroyed all their homes and ruined their lives.
M-C tells Rapunzel that she can go with them, but that Rapunzel has to come back. She wants Rapunzel to spend half of her time with her. It's the summer so she says that Rapunzel has to come back on the fall equinox and stay with her until the spring. And Rapunzel has to come alone.
Rapunzel, extremely confused and frustrated by these terms, submits to them because she has no other choice. M-C feels another flare of anger that makes her demand all the Coronans leave - Corona and everything within the walls is hers now. Her demand is spurred on by the fear she experienced during her rampage, her old memory of being scared of being sent away. So she refuses to leave her home, but she also cannot bear to have the Coronans around her, who had largely been disdainful of her since she was a child for being a tomboy. She is also confusing the Coronans in her mind with vague memories of the other celestials - she thinks they're terrible and cannot be trusted. The Coronans don't have much to stay or fight for, so they take everything they can and leave through the wall's breach.
The Coronans go to Arianna's home kingdom as refugees. Rapunzel and her extended family spend months rehousing people and trying to help everyone build a temporary new life until Rapunzel can get through to Cassandra. Rapunzel goes back to Corona before the equinox to try to talk, but M-C has built up huge walls of black rock where the Corona walls used to be - much higher ones. She even has wavebreakers of black rock that prevent ships from getting to Corona by sea, far off of the shore of the capital's island. The wavebreakers connect to her walls, so her new domain is completely surrounded. No one can go in or see in. Dark clouds hover above Corona, the way they did in the Dark Kingdom.
Unable to do anything else, Rapunzel focuses on helping her people.
Rapunzel is sure that she won't need a full six months to get through to M-C. She is, characteristically and in spite of everything, optimistic. But she and Maximus still take a carriage that has some of Rapunzel's belongings and food supplies when going back towards Corona on the fall equinox. A team of royal guards and her friends accompany her to Corona's edge as well.
"You know you don't have to do this, blondie," Eugene tells her when they arrive at the wall.
"If we believe her threats - which, I don't see any reason why we shouldn't - yes, I do," Rapunzel answers. "It'll be fine, I'll get through to her. We've always been able to make up in the past. And besides, I spent eighteen years with a madwoman," she says offhandedly, looking up at the foreboding black walls. "What's six more months?"
The black rock recedes to form a gateway where Rapunzel's carriage approaches, but M-C's not at the entrance. Instead there are two black horses with glowing blue eyes. When they approach, Rapunzel sees that the horses are made from interlocked pieces black rock like clockwork, and they move almost mechanically. When they stand still they're unsettlingly motionless, like statues. It appears that M-C was serious about Rapunzel coming alone - she won't even let her come in with Max. They unhitch Max from the carriage to let one of the horse specters take his place, and Rapunzel hands off Pascal to Eugene.
Upon seeing the specters, every one of Rapunzel's friends tries one more time to convince her not to go. But Rapunzel tells them it's okay, that Cassandra is her friend and she's sure it will all work out.
And so she passes through the gate, the rocks sealing seamlessly behind her.