Caleb Sinclaire is sitting in a diner, sulking and smoking a cigarette. He begins to break down, but composes himself when he sees his younger brother Peter, a college student on Thanksgiving break whom Caleb is giving a ride home, arrive. Peter has found a new girlfriend, Emma Gainsborough, a psychology major, and Caleb immediately grills him for details, beginning to show an apathetic attitude towards women. Emma and Peter met each other while Emma was on campus meeting some fraternity boys; while Peter says she’s a good girl and nothing happened, Peter immediately perceives her as a whore who was cheating on her boyfriend to be with Peter. After being rude to the waitress, they both drive off to Emma’s house who Peter wants to introduce. On the way, Caleb reveals he hasn’t managed to fall asleep in a week.They arrive at Emma’s house; although she comes off as a sweet girl, Caleb is immediately antagonistic to her and smokes in the car, even though Peter says she doesn’t it. Caleb however, keeps his eyes on Emma when she’s not looking and drops both of them off at his father Donald’s house. Caleb however, refuses to come inside and calls his father by his first name; he also tells Emma that they probably will never see each other again.Donald comes off as a well-meaning polite father, consistently praising Emma. Caleb meanwhile, has been trying to sleep, but keeps getting images of his last girlfriend, Hannah, who behaves and looks strikingly similar to Emma. Hannah has continuously called Caleb, which tortures him, and to get her off his back, sends explicit pictures of himself with a prostitute named Samantha to her house.Caleb, a construction worker, arrives at work and belittles fellow worker JT, who looks up to him. Later, Emma and Peter go bowling and Caleb, who is there with the other workers, secretly watches them. Emma later approaches him asking for cigarettes, revealing she actually smokes and it’s Peter who doesn’t like it. Caleb eventually obliges; Emma asking him to promise not to tell this to Peter, and Caleb asking her to not reveal he was there at all to Peter or Donald.The next day, Caleb’s boss, who happens to be JT’s uncle, tells him to be nice to him because he likes him so much. Caleb later is at a grocery store, and runs into Emma. He ends up attacking her, calling her a whore, believing she’s slept with the frat boys at school, and threatens her not to hurt Peter, who he knows is a good kid(and a virgin). Moments later in the car however, he breaks down ashamed of his actions and goes back to her, begging her forgiveness and not to tell anyone what happened. Confused and outraged, Emma punches him and they both go separate ways.That night, Emma sneaks out for a cigarette, and meets Caleb who tried sneaking over with a camera. Emma wants an explanation on what happened earlier at the grocery store: Caleb goes into his belief on what he heard about her at school, his girlfriend Hannah who cheated on him, and his lack of sleep, feeling himself in a daze between sleep and wakefulness, which has further muddled his actions and behavior. Caleb eventually leaves, feeling better after these series of confessions.The next morning, Donald and Emma go jogging together. Emma asks about Peter’s mother, and Donald reveals that she died when both Caleb and Peter were very young and, Diane, cheated on Donald. Everyone that heard felt betrayed, and when she later was diagnosed with cancer, no-one came to visit her in the hospital the last four months of her life. At work, Caleb reveals he managed to fall-asleep for a few brief minutes the night before. Later, Donald, Peter and Emma are outside when Donald almost accidently shoots Caleb, who has snuck over again with a camera, mistaking him for a raccoon. Donald demands he leave at once.At a restaurant, Caleb, Peter and Emma are together. Caleb and Emma get a few moments alone, and Caleb assures her that he doesn’t have feeling for her. Emma is just confused by his bizarre actions, and Caleb ends up kissing her, wanting now to see her more. Emma says nothing about it to Peter, as Caleb drops them off. He does however, get a few minutes alone with Peter, warning him to watch Emma carefully, because “she’s looking at me”. Peter says he’s in love with her, and Caleb laughs and scoffs at the idea, but nevertheless praises his brother. Caleb apologizes for his ideas that she was a whore and says that he wants to look after him.While Peter and Emma prepare to have intercourse, Peter reveals that what Donald told her is true, except that Caleb was the only one to actually see his mother before she died, and Caleb and Donald haven’t spoken to each other since then. Caleb goes to see Samantha, and asks her if it’s normal to be in love with a perceived image of someone, even if that’s not who they really are (likening Emma to Hannah). Caleb waits outside the house and, sure enough, Emma goes outside for a smoke. Caleb tries apologizing for kissing her and says he’ll try not to bother her anymore. Emma reveals she’s actually locked outside the house, and Caleb manages to get them both inside through a window. Emma falls on top of Caleb, and he tries to kiss her again. She rebukes him and asks him never to see her again. As Caleb returns to his car, Emma returns to Peter, and begins to have sex.At work, Caleb is feeling like he needs a change and leaves work, uncaring if he gets fired. At a bar, JT asks Caleb if he’s had sex with Emma yet, and he says no, but he wants too. He spots some men sexually harassing a women and ends up fighting them, marking a change in him and a new outlook on women. Knowing that Emma is only staying for one more night, Caleb knows he’s running out of time to say or do anything to Emma. However, he confesses to JT that he feels torn out of his need to try to protect Peter. Meanwhile, Peter has been trying, again, to have sex with Emma but finds himself having difficulty and gives up. Caleb drives over that night to see Emma, and this time, she doesn’t rebuke him when he kisses her, and eventually, end up having sex together.Emma asks why Caleb was the only one to see his mother before she died: He reveals he was just as hurt by her actions as anyone, and shut her out of his life. However, he eventually discovered that Donald had actually been the one cheating on her until she finally had enough. Caleb never told Peter because he was too young. Caleb laughs because he used to think Emma never had sex before, until her expression shows that she actually was a virgin before. He immediately gets up to leave, reminding her that Peter is in love with her. On his way out, he runs into Donald who deduces what happened and says he’ll tell Peter. Caleb says that he won’t because he’s also his son as well, and calls him a coward for erasing him out of his life for finding out what he did; in the last 8 years, he’s only lived two miles away from his house, yet he never attempted to re-enter his life. They both hide quickly as Peter goes to Emma’s room, and Caleb says that he won’t tell Peter what he did, otherwise he’ll tell him Donald’s secrets and he’ll lose both his sons. Peter and Emma sleep together, and he at last, loses his virginity to her.The next morning, Donald drives them to the train-station back to school. Donald confesses to that he’s made mistakes to Peter, and that sometimes, people know what they are doing is wrong but they do it anyway, because the right thing is painful. On the train, Peter tells Emma he loves her, but it causes Emma to cry. The two of them alone again, Caleb rings Donald’s doorbell and Donald invites him in, their relationship beginning to mend at last.