Izzy turns at the mention of her name. Its Lydia, striding towards her, the click, click of her heels echoing in the empty institute hallway. She feels betrayed by the way her heart skips a beat at the sight of her brother's fiancée.
"Can I speak to you?" the other woman asks, then, glancing at Alec who had been walking with Izzy, "Alone?"
Izzy frowns but agrees. They leave Alec to commandeer the nearest empty room. They stand there in a awkward silence for a moment.
"I have a plan." Lydia says, abruptly.
"A plan? For what?"
Of course. Izzy was in charge of the decorations. Of course.
"What are you willing to do to get Alec out of it?"
Its not the question she was expecting, but there's no point in lying.
"Would you be willing to marry me?"
"Ex-Excuse me?" Its not quite as eloquent as Isabelle would have liked it to be.
"I'm sorry, I just- Look, I like Alec, right? But not enough to marry him. But, you, I really, really like you. If I marry Alec, the both of us are eventually going to resent the marriage, and possibly even each other. But... if I marry you... I- I don't know. You probably don't even like me. This was stupid. I didn't think this through at all."
"No!" Izzy cringes at how loud she sounds. "No, I think that's-that's a great plan. I like you, too, and if I marry you, the Lightwoods can keep the institute, and Alec..."
"Alec can see Magnus?"
Isabelle blinks. "Yeah, he can. How did you know?"
"Magnus isn't exactly subtle, and neither is Alec, honestly."
"True. I suppose a marriage between us would have more benefits than a marriage between Alec and you."
"So, are we doing this?"
"We're doing this."
The sanctuary of the institute is humming with excitement and soft chatter. Alec feels restless, can't stop playing with the sleeves of his tuxedo.
His mother approaches him and tells him that she's proud. He can't find it in him to be happy about that anymore.
"You ready?" Jace asks.
Not at all.
"As ready as I'll ever be."
Alec steps onto the altar. He sees Clary, and his mother and his father. He sees the mundane (he just doesn't seem like a vampire), dressed in a jacket that's far too nice to be his. Alec assumes it's his vampire boyfriend's.
"The ceremony is about to commence." declares the Silent Brother, and he has never wished for death more than in that moment.
Isabelle walks in, beautiful as ever, but the smile she's wearing doesn't meet her eyes. Lydia follows, just as beautiful, even Alec can say that, but as she gets closer all he feels is dread. For one short, dumb moment, he wishes he was with Magnus, sharing drinks and subtle flirting. But that's ridiculous, he reminds himself, and impossible. This marriage will benefit him and Lydia both. This marriage is for his family.
Lydia reaches the altar. His self-imposed doom is upon him. They exchange bracelet and necklace. Alec doesn't notice the way Izzy nods slightly at Lydia.
"It is time for Alec Lightwood and Lydia Branwell to mark each other with the Wedded Union rune. A rune on the hand, a rune on the heart, a union is born."
She takes the stele, touches it to the crystal and positions it above Alec's wrist.
Lydia looks at him, smiling softly. He tries to smile back, but it comes out looking more like a grimace. This isn't how you're supposed to feel at your own wedding, is it?
Just before stele meets skin, Lydia turns around and draws the rune on Izzy.
"Uh.." Alec says, elegantly. Izzy takes the stele and repeats the process on Lydia. The murmurs from the crowd are confused mostly, but some sound outraged. He doesn't dare look at his mother.
"The ceremony is complete." Brother Jeremiah says, sounding it's like a question rather than a statement. "Isabelle Lightwood and Lydia Branwell are now wed."
As if this wasn't already plenty bizarre, the door chose that time to slam open. Magnus walks in, stopping abruptly, looking from the confused Shadowhunters, to Lydia and Izzy, and then to Alec. His eyes ask a question Alec couldn't answer for the life of him.
So he doesn't. Instead, he steps down from the altar. His mother stops him.
"Alec, what are you doing?"
"Enough. I can't get married to Lydia if she already has a wife, right? So, enough. I'm done, Mother."
And with that, he strides over to Magnus, grabs him by the lapels and kisses him with everything he's got.
Behind him, Isabelle takes Lydia's hand.
"He deserves to be happy. Besides, I'm more than content with the Lightwood I have."
"Well, you better be, 'cause we're hitched for life."
Lydia laughs, loud and bright. Izzy finds herself falling for her a little more.
"Yeah, I guess we are."
Lydia rests her free hand on Isabelle's cheek and kisses her gently, a simple brush of lips. Isabelle thanks the day Lydia Branwell (Lightwood-Branwell, now, and the thought makes her dizzy with glee.) walked into her life.