It starts one afternoon at his apartment, when she insists he read an article in Cosmo. He gets a paper cut from the magazine and, without thinking, she puts his finger in his mouth and sucks on the wound. A full minute passes before either is able to speak, and as she blushes and apologizes, all he can think about is that she's the first woman he's ever made blush. It isn't until after she leaves, mumbling something about burning food, that he thinks of bacteria and washes his finger off.

A week later, she catches herself daydreaming about the event for the fourth time as he hits her with a melee attack. He asks why she's having so much trouble with Halo, and she's so startled that she dies by her own plasma grenade. When the game ends, he's ahead of her by thirteen kills.

He notices that her behavior is increasingly bizarre and wonders if he is the cause. He catches her on her way into her apartment and demands to know what is responsible for the recent anomalies in her conduct. She slams the door in his face, and he concludes that a hypothesis is necessary for further research.

She waits until he has gone back into his own apartment to relax. She knows it's absurd to be hung up on such a trivial thing, but she can't help herself. She's become incredibly aware of him, and she wonders if the attraction might have been there all along, hiding. The idea scares her a little bit.

After a thorough examination of their recent encounters, he concludes that the brief contact between them has triggered some sort of attraction in her. Daunted by the notion, he puts off thoughts of dealing with it; after all, a hypothesis is meaningless unless it has been tested and proven.

She is thoroughly shocked when he kisses her in the middle of Thai night. She's not the only one. After a moment, she regains her composure and slaps him before storming out of the apartment. When she arrives back at her home, she puts a finger to her lips and realizes that it was kind of nice.

He reconsiders his hypothesis.

She spends the next few days avoiding him as she tries to sort out her feelings. On the third day after the kiss, she wakes up from an erotic dream and surmises that she really is attracted to him after all.

He arrives at the conclusion that it was repulsion, and not attraction, that accounted for her change of attitude a day later. As he's collecting his mail, she taps him on the shoulder. After his shock wanes, she throws her arms and his neck and kisses him.

He reconsiders his hypothesis.

He determines that, with her attraction established, he must plot a course of action. Whatever his chosen path, he must tread delicately or risk upsetting the careful balance of their friendship. He spends several days considering the matter before he realizes that the woman who has taken to sitting in his lap and slipping her hand into his has effectively chosen a path for him. He decides to continue down it and see where it leads him.

Although he adjusts to most aspects of dating fairly quickly, it's four months before he becomes entirely comfortable with the constant physical affection that is demanded by the relationship. She becomes aware of this newfound comfort, and begins to drop hints about progressing to the next level of intimacy. He blatantly ignores them all.

They reach six months, to the surprise of their friends. She insists that they celebrate their 'halfiversary' by going out. They stumble drunkenly into her apartment late that night and have sex for the first time.

The next month sees her holed up in her bathroom, sitting on the closed toilet. She stares in apprehension at the pregnancy tests littering the floor around her ankles. All are positive.

He nervously clutches a bouquet of daffodils as he knocks three times on her apartment door. He knows that roses are more traditionally romantic, but he also knows that daffodils are her favorite flower. In the middle of the bouquet, nestled between the bright blossoms, is a small velvet box.

He's familiar enough with the law of large numbers to know that there's no such thing as fate, but manages to bite his tongue all the same when she says it's what made him propose right before learning of her pregnancy. Then he does a double take, asking her to repeat the last part, and finds that the news doesn't seem to dampen the moment at all. In fact, both find it oddly exciting.

He calls his mother with the news, and is ordered to 'do right by her', even though he explained the engagement before the pregnancy. He can tell she's torn between happiness for him and disappointment in his irresponsibility. He assures her that he loves his fiancée very much, and she seems content.

She spends the morning before the ceremony sobbing as she realizes that her family isn't coming. His mother awkwardly attempts to comfort her, but it's his twin who is able to convince her to proceed with the wedding. She nearly breaks down again as she walks down the aisle alone, but makes it through all the same. She manages to forget about it and enjoy the reception.

She spends the first night of their honeymoon crying into his shoulder.

They decide to split the baby naming task in half – each gets to decide a name for one sex, and whichever the baby is, it's what they'll go with. They flip a coin. He gets girl, she gets boy. Neither minds it one bit.

He wants to name their child after his mother. He doesn't quite remember what her choice was; Josh or Jake, perhaps. All those generic J names sound the same to him.

Five months later, John Cooper is born six weeks premature. For the next month, neither he nor his mother leave the hospital. His father is rarely present. When he does visit his son, she notices a strange look on her husband's face that she's never seen before and can't identify.

Two days after coming home, John passes away in his mother's arms. His father is busy with an experiment at work and doesn't answer the phone. He doesn't learn of his son's death until he arrives home late in the evening and finds his wife grieving.

That night, she buries herself in his arms and begs to be comforted. He isn't sure what to do, and says the first thing about their baby that comes to mind. He only realizes when she slaps him that he got his son's name wrong.

She never does tell him that she named their child after John Forbes Nash.

He throws himself full force into his work. He tells himself it's because he's on the verge of a breakthrough, though he's sure she believes that he's avoiding her. He doesn't pause to question why she hasn't confronted him about it.

A month passes before he realizes that she isn't speaking to him. It hurts him, but he pretends that he hasn't noticed, and begins spending even more time at work. Some nights, he doesn't even come home. She cries herself to sleep those nights.

She can't stand the distance between them and begs him to take time off. He refuses, saying that he's indispensable at work. She doesn't press the matter. On the inside, she wonders if he'll ever realize that he's indispensable to her.

When his big project bottoms out, he has no more excuses to stay away from home. He wishes he was better at lying and considers calling Leonard to ask for advice, but he doesn't want his best friend to know that he's having marital troubles. He comes home and finds out that Leonard already knows; she wants to separate for awhile, and is staying with their mutual friend.

She knows she's a coward for running away instead of confronting him, but she's terrified that if she does confront him, he'll decide that he no longer wants her. Every time the phone rings, she prays that it's him, calling to beg her to come home. The only call she gets in the three weeks that she's there is from her boss when she stays home sick.

The house feels unnatural and empty without her, but he doesn't dare admit it. After he's worked so hard to distance himself from her, he can't bring himself to ask her back.

She decides to get her own place after she realizes that he's not going to come for her. The first apartment she looks at is the nicest, but when she meets the tall, nerdy manager, she knows it's not the right place.

Even though he hasn't spoken to her in months, it feels like a blow to his gut when he is served with divorce papers. The knowledge that it's his own fault doesn't help at all.

The divorce is finalized, and she becomes a mere statistic. No one cares that she lost her baby and her husband. She's just another single woman with emotional baggage. She falls back into promiscuous habits, but she never dates any more. She doesn't think she'll ever be able to let go of him completely.

He falls out of contact with every friend they have in common. He tells himself it's for the best, and that all a relationship really does is compromise one's work and prevent progress. He spends the next two years reinforcing this, and almost believes it until he passes a blonde woman at the grocery store with a flower barrette and realizes that he can't live without her.

She's no longer able to pretend to be satisfied by a stream of meaningless sex. She's tired and lonely and ready to give up.

He shows up on her doorstep with a handful of daffodils. They hug and they cry, and they both know that they never really stopped loving each other.

Her father offers to walk her down the aisle this time, but she declines. Instead of holding another ceremony, they go to the courthouse and remarry in front of a judge. They're ushered out before they can even kiss, and someone's child spits on her, but she still thinks it's the most wonderful day of her life.

They're both afraid to try for another baby, but once again, fate intervenes (he no longer bothers to question the term), and she finds herself with child. This time, there's a happier ending, and after a healthy nine months, she gives birth to a healthy baby girl. He wastes no time in getting to know his daughter.

At six years old, Mary wanders into her father's study and asks how he and her mother met. He tells her about the pretty blonde girl who moved in next door to him so many years ago, and his wife enters the room to tell her little girl about the beautiful mind she moved in next to. They share a private look at that, one which Mary doesn't really understand, but she quickly forgets as they continue the narrative.

When twelve year old Mary gets her first crush, he battles with an irrational desire to break the legs of all the boys in the neighborhood. He explains to his wife that the idea of his daughter dating scares him, but she only laughs. Secretly, she's a little bit worried too.

It isn't until she's sixteen that Mary actually gets her first boyfriend. Her father approaches the boy and orders him to explain string theory in one hundred words or less. She's afraid that her boyfriend will wet himself until her mother jumps in with an assurance that it was a joke. He's surprised, because he hadn't intended to joke.

The first thing Mary does when she graduates is move out. Her father takes her and her things to hew new apartment, and as they're unpacking, two young men from the room across the hall offer to help. He's tempted to chase them off until a wave of deja vu washes over him, and he's reminded of when he met his wife. With a curt nod to the boys, he takes his leave. When he gets home, he tells his wife that he has a good feeling about things.