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Modus Tollens

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"And this one," Ami said, "is called modus tollens."

Usagi followed the line of Ami's finger to see what she was pointing to. She found the spot in her textbook and read aloud, "P-horseshoe-Q, tilde-Q, tilde-P." She stared at it for a long moment, then looked sheepishly up at Ami and said, "I don't get it."

Ami smiled, ever patient. "Modus tollens states that if a conditional statement is presented, the consequent of which is then negated, the antecedent must also be negated." When Usagi stared at her blankly, she hastily added, "Which, of course, means that if the first proposition is 'if P then Q,' and the second proposition is 'not Q,' then it follows necessarily that the conclusion is 'not P.'"

Usagi gave a small nod, but she still looked concerned. "Okay, I get that, but why? It doesn't make sense to me."

"Think of it this way," Ami said. "Let's say... U-horshoe-M. If Usagi gets good grades, then Mamoru buys her ice cream."

At this, Usagi nodded excitedly.

"But then let's say tilde-M. Mamoru doesn't buy Usagi ice cream."

Usagi's smile faded a little, but she kept listening.

"From that, we know that the conclusion is tilde-U, because if it's true that Mamoru will buy Usagi ice cream if she gets good grades, but then he doesn't buy her ice cream, it must be the case that she didn't get good grades."

For a very long moment, Usagi was completely silent, her head tilted slightly and eyes screwed up in an expression of deep concentration. Then her face lit up into a huge grin and she exclaimed, "I get it! So you're saying that if this one thing makes this other thing happen, but that second thing that's supposed to happen if the first thing happens doesn't happen, it's because the first thing didn't happen!"

Ami couldn't help but smile back. Usagi's explanation might not have been quite as succinct, but she was still correct. "Very good, Usagi-chan. You've got it. Now what was the name again? Without looking!"

Usagi supplied tentatively, "Modus... ponens?"

"Close. Modus tollens. Modus ponens is the one without the tildes."

Usagi gave a sigh and propped her chin in her hands, eyes downcast. "It's hopeless. I'll never get this stuff in time for the exam."

Ami reached across the table to take Usagi's hands in her own, channeling all of her warmth into her smile. "Don't think like that, Usagi-chan. You're doing very well. You've got almost all the rules memorized, and that's the most difficult part! Now you just have to remember the names, and you'll be fine."

Usagi held tightly onto Ami's hands. "Do you really mean that?"

"Absolutely. I'm very proud of you, and just think how proud Mamoru-san is going to be when you show him those exam results!"

All at once, the joy came rushing back into Usagi's face. "Ami-chan, you're the best tutor ever!" She stood from the table and enveloped Ami in a tight hug—then gasped loudly and stumbled back, hands grasped against her chest as if she'd been shot. "Ami-chan," she squeaked, "it's so late! Mama's going to be so upset if I'm not home soon—"

In the next moment she was gathering her things and stuffing them into her bag at top speed. She gulped down the last of her hot cocoa and gave Ami one last hug, and called on her way out the door, "I'll see you tomorrow, Ami-chan! Thanks for everything!"

Left in the aftermath of Typhoon Usagi, all Ami could do was smile. She began to pack up her own things, thinking that Usagi was right and that she should go home to get some sleep, but she wasn't very tired, and the coffee shop was warm and the classical music playing softly helped to relax her. She put most of her books away but kept her Introductory Logic textbook and a pad of paper out, and after she ordered another cup of tea, she began to work some exercises from the back of the chapter they'd been reviewing. Even though helping Usagi was a form of studying in itself, it wouldn't hurt her to spend some extra time on some of the higher-level problems, and before long she was scribbling away in her notebook, lost in the peaceful music and the warm tea and the comforting pattern of letters and symbols rearranging themselves in her mind.

Ami wasn't sure how much time had passed when she heard a familiar voice ask from beside her table, "Mind if I join you?"

She looked up from her book to see Mamoru standing there, bundled up in his jacket and holding a book bag in one hand, steaming cup in the other. Her heart skipped a beat at the sight of him, and she remembered that his flat was nearby. She scolded herself for forgetting such a thing and quickly forced a friendly smile onto her face. She said, a little breathlessly, "Good evening, Mamoru-san!"

He smiled back in his usual, warm way. "I was just grabbing some coffee on my way back from the library when I saw you. I figured I'd stop in to say hello."

"That's very kind of you. I hope I'm not pulling you away from anything important—"

"Ami," he laughed, setting a gentle hand on her shoulder, "I wanted to say hello. I could have kept on walking."

Ami didn't know how to respond to that. Her eyes lowered and focused on the bag in his hand. "What did you pick up at the library?" she asked, relieved to have found a change in subject.

He carefully emptied the contents of his bag onto the tabletop, revealing an armful of books on fairytales and folklore. "I'm writing a term paper on European folklore," he said, "so I figured I'd pick up some research material."

Ami sifted through the books, looking over the titles. Peter Pan, a collection of essays on the beauty and the beast, a Hans Christian Andersen anthology... "What's your thesis?" she asked.

Mamoru tutted quietly. "Not sure yet. I want to do something about the portrayal of romantic love, though."

"That sounds very interesting." She looked up at him with a smile. "I'd love to read it when you're finished. That is, if you don't mind."

He returned the smile easily. "Not at all." He slipped into the chair across from her, pulling a book from the bottom of the pile and setting it on top of the others. "This is going to be my primary source, I think. It's my favorite story of them all."

Ami looked down at the book he had chosen, recognizing the illustration before she even read the title. The picture on the book's cover was of an elegant young man in regal armor, standing poised over a canopied bed where a sleeping princess lay with hands folded over her torso, a serene expression on her pale face. Ami knew just from the image that this was the story of Sleeping Beauty. "This is your favorite?" she asked, glancing back up at Mamoru.

He smiled a bit sheepishly and nodded. "There's something about the story that has always struck a chord with me. Something about two people being destined for each other, to the point that even though they've never even meet, their love is so deep, so powerful, that just a kiss from one could wake the other from an impenetrable slumber..." He gave a slight, bashful shrug. "I'm somewhat of a romantic, I suppose."

"Don't be embarrassed," Ami said. She wanted to tell him that she too had always been particularly fond of the story, but that they were very probably drawn to it for different reasons: he because he had someone like that, and she because she did not.

Instead she told him, "It's a beautiful story."

All the shyness drained from his expression, and with him smiling at her like that, it was Ami who found herself feeling bashful. She looked down into her own book before she could start to blush, and in her periphery she saw Mamoru lean over the table and glance at the pad of paper onto which she had been writing. "What are you working on?" he asked.

"Oh, this?" She looked over the letters and symbols that were stretched down the length of the page. "It's propositional logic. I'm just working on my derivation skills. It's been a while since I've practiced, so I decided to go over some proofs..."

He blinked owlishly at her. "You do proofs for fun?"

She felt the telltale warmth of a blush beginning to creep along her face, and glanced back down into her notes before it could spread any further. "Well, yes, but it's been so long—I'm afraid I'm a bit stuck."


"Mm," she nodded. "I'd already been looking at this one for a full minute when you came in."

He asked slowly, "How long does it usually take you to complete one?"

"About forty seconds," she said, and then when his eyes widened, "I mean, to solve it. It takes some more time to actually write everything out, of course."

"Of course," he agreed, giving an exaggerated nod. He peered closely at her notes and made contemplative hmm noises for a few moments before pointing to two of the lines and saying, "Maybe if you conjoin these two, you could use the rule of constructive dilemma and—"

Ami gasped, her eyes going wide. "And distribute that to turn it into a disjunction, then use DeMorgan's law on the first disjunct, which would make it a negation, meaning I could use implication on the whole thing, thus turning it into a conditional and allowing me to use modus tollens along with line three to reach my conclusion!"

Mamoru laughed quietly. "I hadn't thought that far ahead, but yeah."

She snatched up her pen and immediately began scribbling, but she paused after the first line to look back up. "Mamoru-san," she said, "I didn't realize you were interested in propositional logic."

He shrugged and smiled. "Well, I am a man of mystery."

Ami felt her fading blush creep back up. She cleared her throat and went back to writing out the lines of her proof, saying as she did, "It's getting a bit late. I should probably head home once I'm done with this."

When she closed her book and began packing it into her bag, he pushed his seat back away from the table and made as if to stand. "I'll walk you, then."

"Oh, Mamoru-san, you don't have to—"

"Don't worry about it," he said, smiling dazzlingly. "I'm not quite ready to head home, anyway."

She packed the last of her things, and they finished their drinks, and together they strode out of the warm coffeehouse and into the crisp air outside. The night around them was still bustling with people and activity, party-goers moving from one scene to the next, young couples holding hands and embracing along the tree-lined walkways that led into and out of the small square. Ami turned in the direction of her apartment, half-expecting Mamoru to bid her goodnight and head for his own flat, but he turned right along with her and continued at her side.

They were not standing closer than any two friends might, and she could still feel the warmth radiating from his body.

"Nice night out," he said.


"The weather should start getting warmer soon, but right now it's very comfortable."


"Are you all right, Ami?"

She looked up at him, eyes a little wide. She had not been expecting the question. "What do you mean?"

"You seem... distracted."

For a long moment, Ami did not know how to respond. So many thoughts were floating in her mind, but none of them were things she would like to say. She didn't want to tell him that she had always felt herself drawn to him, almost the same way she was drawn to Usagi but different somehow, different in the way that she looked forward to the times he accompanied Usagi to Crown Royal, different in the way that she felt she could say and do things around him that she couldn't around the girls because they would only roll their eyes or laugh—That's our Ami-chan, always thinking about school—but he never did. He may have been taken aback by her enthusiasm for doing proofs, but then he helped her solve one, and she couldn't think of anyone in her life who might have done the same.

She did not say any of these things. Instead, she did what she would do in any scenario: She assessed the situation. She compartmentalized. She dealt, as she always had, with the loneliness with which she had become intimately familiar. She took it in and made it her own, used it to fuel her, used it to keep her going, keep her motivated, keep her thinking that maybe, some day, if only she worked hard enough, she might have a Prince Charming of her own.

"I'm fine," she said.

Somewhere up ahead, someone screamed.

The two of them shared a quick glance, all thoughts of small talk long gone, before sprinting in the direction of the shout. A few meters up ahead, in a clearing outlined with park benches and dotted with terrified people, stood what looked like a huge, humanoid scorpion.

Even in the absence of a major villain, the occurrence of a stray monster here or there was something the Sailor Senshi had come to expect. The vestiges of darkness that lingered from their various enemies had accrued over the years to create pockets of negative energy throughout the city, pockets which sometimes caused strange things to happen or which spewed out the occasional abomination. It was not unheard of for a small animal to walk through one such space and emerge as a monster, and this appeared to be the case with the hideous creature that stood before them.

It was still a bit unusual to see one in an area like this, but Mamoru and Ami didn't waste time dwelling on this fact. As the monster approached a frightened couple on the other side of the clearing, Mamoru summoned one of his roses and shouted, "Hey, ugly! Over here!"

The monster turned slowly to look at him. It was a hissing, insect-like thing, nothing like the brightly-colored and often silly creations they had grown used to in their earlier years. As it turned out, without the guiding hand of a theatrical megalomaniac to oversee their creation, these monsters tended to be quite a bit more frightening than any youma, phage, or anything else they had faced in between. This one in particular stood hunched on two legs, a tail swaying behind it, with several long, many-jointed arms sprouting from its torso. Its twisted body was covered in a dark, glistening exoskeleton, its mouth was filled with huge sabreteeth, each of its arms was tipped with sharp claws, and on the end of its tail, now arced high above its head in what looked very much like an offensive stance, was a dripping stinger. Truth be told, it looked more like one of the creatures from Mamoru's fairytales than whatever it is they had been expecting.

Mamoru blanched at the sight of it, but recovered quickly enough to throw his rose before the monster lost interest. As usual, his aim was true. The unnaturally sharp point of the rose struck the monster square in the chest, finding one of the weaknesses in the hard armor as if it knew where to look. It wasn't enough to cause much damage, but then again, that wasn't the point; it was enough to redirect the monster's rage, and as it lowered itself onto its several arms and began scurrying towards the two of them, the couple it had been looming over took their opportunity to scramble away to safety.

As soon as they were alone in the clearing, Ami wasted no time in summoning her Crystal Change Rod and transforming. Mamoru, however, was not so lucky. Her transformation ended just in time for her to see the monster pounce and pin him to the ground. Before either of them could move, the monster raised its tail and struck swiftly, the sharp point of its stinger piercing through Mamoru's clothes and embedding itself in the juncture of his neck and shoulder. Mamoru gave a choked cry and a feeble jerk, and then went very still. His eyes drifted closed, his head lolled to one side, and his body went limp beneath the monster.

Sailor Mercury's breath caught in her throat. She had to make sure he was okay, that he was still breathing, but she knew that if the monster was that quick, she had no hope of helping Mamoru if she didn't lure it away first. Remembering Mamoru's rose, she threw out a Shine Aqua Illusion—it wasn't her strongest attack, but it would turn the monster's attention onto her—and started running. She heard the monster roar in pain, and then she heard its many limbs skittering against the ground as it scurried after her.

Her hands were just shaky enough to make handling the communicator difficult, but after a moment Usagi's face appeared on the little screen. "Ami-chan, what's wrong?"

"No time to explain, Usagi-chan." She glanced over her shoulder to find that the monster was quickly gaining on her. "I'm in the park, near the coffeehouse—get here quickly!"

Usagi nodded once, and then the screen went blank.

Mercury hadn't crossed as much distance as she would have liked, but she knew that she wouldn't be able to stay ahead of the monster much longer. She darted behind a tree and cast Shabon Spray before the monster could reach her, and immediately the area was filled with a dense fog that allowed her to slip away from the roaring, blinded monster and make her way back to Mamoru. Her visor helped guide her path through the mist, and when she found Mamoru, she was relieved to see that the vitals which appeared on her screen indicated that he was still alive. His heart and lungs were working only weakly, but they were working.

She knelt at his side and slipped her arm beneath his shoulders, straining with the weight of him but managing with some effort to pull his upper body across her lap. "Mamoru-san," she gasped, shaking him gently. "Mamoru-san, wake up!"

He gave no response. Not a fluttering eyelid, not a twitching muscle. Nothing.

Despite her best efforts to stay calm, Mercury felt herself begin to panic. She had no doubt that she could hold the monster off until the girls got there, but if she were to let something happen to Mamoru, if she were to lose him... She would never forgive herself.

She forced herself to breathe calmly in an attempt to let her mind clear. Usagi was always saving people from things like this, often just by being Usagi. Mercury thought hard and imagined what Usagi might do in this situation, what the Princess might do to wake her Prince from an impenetrable slumber.

It was a long shot, she knew, but she attempted to justify it by reminding herself of all the silly and nonsensical opponents they had fought in the past and that, really, this would not be the strangest way she'd ever had to save someone. Considering how unlike their previous opponents this monster was, that thought didn't do much to quell her doubt.

She tried it anyway.

Mamoru's hand was warm when she held it in one of her own, her other hand tilting his head back as she angled herself above him, leaning down just far enough to press her lips to his. She closed her eyes and held the kiss, remembering every stuttered heartbeat, every loving thought she'd ever had, channeling it all into her fingers wrapped around his hand, her mouth pressed against his—trying to summon a love so deep, so powerful—

Nothing happened.

She wasn't sure what she had been expecting, what she had been hoping would happen, but when nothing did, her heart sank.

A hiss sounded in the distance, and when she looked in that direction, her visor supplied the flashing outline of the monster that was approaching through the fog, its tail raised high. She gripped Mamoru's hand tightly in hers and swore that she would not leave him again.

The monster grew close enough that she no longer needed her visor to see it through the mist. She readied herself to throw out an Aqua Rhapsody and hoped it would be enough—but the need never came. From somewhere behind her, a spiraling ball of fire cut through the air and hit the monster head-on, burning away the fog and reducing the monster to a screeching, sizzling mess within a matter of seconds. Mercury knew without having to look that the other Senshi had arrived.

For a moment, the clearing was silent but for the low hissing of the monster as it stood still, sizing up each of its new prey. Then it moved, and the instant it did, Mars, Jupiter, and Venus were springing into action, hitting it with everything they had and giving Sailor Moon the time she needed to check on Mamoru. She rushed to Mercury's side in a swish of skirts and feathers, her eyes wide, hands gesturing nervously. "Sailor Mercury, are you okay? Is Mamo-chan okay? What happened?"

"Slow down," Mercury gasped. She let Sailor Moon take Mamoru into her own arms, let her hold his cheek and look into his face, and the look of love in her eyes was so clear, so undivided in its focus on him, that Mercury almost thought Sailor Moon might not hear her when she said, "We ran into each other after you left, and that's when it showed up. It stung him, and he's still breathing, but—I haven't been able to wake him up—"

"Oh, Mamo-chan." Sailor Moon kissed his cheek and hugged him tightly, little tears welling in her eyes.

"I'm sure he'll be fine," Mercury said. Her hands were still hovering awkwardly where they had held Mamoru. She wasn't sure what else to do.

From the center of the clearing, Mars's voice called out, "Sailor Moon! We could use your help right about now!"

Sailor Moon gave a determined nod and hefted Mamoru back into Mercury's arms. Then she was off, summoning her Eternal Tiare and leaping into the fray, no doubt preparing some overly eloquent speech to deliver before finally using her power to cleanse the poor creature of whatever dark energy had turned it into this.

In Mercury's arms, Mamoru began to stir. His eyes fluttered open and he tilted his head up to look at her. His eyes were surprisingly clear for someone who had just woken from a venom-induced nap. As he slowly pulled himself up, his movements sluggish though not sleepy or disoriented, Mercury could scarcely breathe for the relief that was washing over her. She helped him to his feet and let him brace himself on her shoulder until he found his footing, and neither of them said a word, and before long Sailor Moon was bounding back towards them with the girls in tow behind her, jumping to envelop Mamoru in a hug that would have sent them both tumbling if it weren't for Mercury's hands at his back, steadying him.

When she realized that she was still holding him even after he had regained his balance, she stepped away and drew her hands behind her back, trying to suppress the blush that was beginning to surface.

"Oh, Mamo-chan," Sailor Moon was gasping, "I'm so glad! Are you all right? Are you still hurt? Do you need to lie down? You're so weak!"

Mamoru laughed quietly, returning the hug if a bit gently. "I'm fine, Usako," he said. "The monster didn't actually knock me out, just paralyzed me. It should finish wearing off in a few minutes."

Beside them, Mercury felt her face break into a magnificent shade of red. "P-paralyzed?" she squeaked. No one seemed to hear her.

"Mamo-chan, you must have been so frightened!"

"I knew I was in safe hands," Mamoru said, and though it only lasted for a moment, Mercury swore she saw him glance up at her and smile.

Sailor Jupiter thumped her over the back as if trying to help her through a coughing fit. "Oi, Mercury, are you all right? You seem a bit flustered."

"Yeah," Venus chimed in, "did the monster get you, too?"

"I'm fine," she stammered. She kept her eyes locked on the ground, and they must have been able to see through the lie but if anyone did, they didn't comment on it.

After that, things progressed as usual. The girls joked around while Sailor Moon fluttered over Mamoru, and then they all started to go their separate ways. Mars, Jupiter, and Venus bid Mercury goodnight before wandering off to change back and head home, while Sailor Moon commented that she would phone to let her mother know she'd be back in the morning so that she could keep an eye on Mamoru throughout the night. Then they were leaving as well, heading towards Mamoru's flat, and no one seemed to notice that Sailor Mercury was red-faced and silent and that her hands were shaking just a little.

She found a quiet alley where she changed back into Mizuno Ami, and she walked home and prepared a cup of tea and drank it in her kitchen, and then she drew a bath and slipped into the tub, sighing at the relief of the cool water on her too-warm skin and thinking still of Mamoru and his hand gripped in hers and her lips pressed to his.

She tried very hard not to think of how he had been conscious the entire time, awake but unable to react, unable to respond.

And she most definitely did not think of how he might have responded if he could.

She did not stop blushing until long after she finished her bath and climbed into bed.