After leaving a party at a women's dormitory (aka the "virgin vault"), Matthew (Jonathan Tucker) is trapped in an elevator with an unknown, and unseen, woman when the power goes out. Matthew and this unknown woman have sex in the dark. When Matthew wakes up in the morning still in the elevator he finds himself alone with a pair of her panties.
On a mission to find his mystery maiden by finding a matching bra for the panties, Matthew becomes the maintenance boy of the virgin vault. He releases mice and goes room to room setting traps. He convinces the panicked women to leave the room and then starts to look for a match. This does not prove successful, and he continues to break things (such as the air conditioning) in an effort to find his woman. He also fixes the television set, which is greatly received by women he refers to as "Jane-ites," as they have a great interest in movies adapted from books by Jane Austen. He doesn't get much help from his roommate Rod (James DeBello), who keeps telling him to give up, and together they philosophize about men and women. Rod tells him that he doesn't need a girlfriend and that it's futile to try to find the "matching bra the panties," and Matthew accuses him of being too machismo. Rod introduces Matthew to his adopted idea of "penile power" that he uses to try to increase the size of his penis. We later find out that he does this, as well as the dissing of women entirely, as a ploy to try to make himself feel better about the problem he has with his manhood.
Early on, he watches as a woman named Patty (Emmanuelle Chriqui) and her boyfriend Crick fight. Crick is the epitome of the macho man stereotype, with his big pectorals, conceited attitude, and abusiveness. He wears a pony-tail, a manicured goatee, "male make-up," and chews nicotine gum, much to Matthew's dismay. Matthew tries to save Patty, but is hurt by Crick. Crick leaves and Patty tries to help Matthew, but Matthew can't help but think of how Patty's reputation has been.
While searching one room, Matthew finds himself trapped in the bathroom when the occupant returns. Matthew is attacked by Wendy (Larisa Oleynik), until she recognizes him as a high school classmate. Wendy decides to help Matthew in his quest to find his mystery maiden. Later we learn that she is also looking for a woman because she is a closet lesbian.
Along his quest, we learn of his nervousness he has had to talk to girls. He gets scrutinized by Arlene (Katherine Heigl) and his teacher Ms. Stern (Aimee Graham) about how females are more dominant than males are. Arlene undermines him and beats him at fooseball and Ms. Stern preaches about how the female gender is more dominant and should be in command, rather than males. Rod even tells Matthew that he's a chicken and should just give up on girls, while Matthew tells him that he has never been able to speak to girls, especially Cynthia (Jaime Pressly).
In addition to searching by hand, Matthew puts an advertisement in the school newspaper to meet him in the basement on a Thursday night. He ends up sitting in the dark every Thursday night just waiting for her to show up. The door opens one night and he thinks it's her, but it turns out it's just Wendy coming to check up on him. Then, one night, the mystery maiden shows up, only to tell him to stop looking for her.
Despite the end of the semester approaching Matthew isn't detered and disguises himself in drag to keep searching. In drag, he is actually able to talk to Cynthia one-on-one which, otherwise (until she is injured later on) he is not able to do because of her looks. He also gets checked up by Rod, who claims to the regular Matthew that he had sex with Matthew's drag character, for which makes Matthew so mad he adds a higher weight onto Rod's "penile power," hurting him there. Crick makes a pass at Matthew in drag as well when he is fighting with Patty, and Matthew ends up biting part of his tongue off as a result, making Crick unable to speak.
Desperation has set in, and so Matthew appeals to his mystery maiden by proclaiming his love for her to the whole dormitory. Afterwards he determines his mystery maiden is Patty the same one he's had sex with since the elevator incident. She initially rejects him because she thinks that he only sees her as some slut. Crick sees that Matthew wants Patty, but Matthew says that he'll have him arrested for sexually assaulting him. Not too much later on, Patty warms to Matthew after he tells of his undying love for her.
In the end, Arlene and Wendy end up together, and Rod and Dora, intentionally put in the same situation as Matthew was in by Matthew himself, end up together as well. Cynthia shows off her newly found martial arts abilities, and Ms. Stern learns a valuable lesson on gender equality, as Matthew stands up to her in front of the class, to a unanimous ovation.