Watch American Psycho II: All American Girl Online

The movie starts with a twelve-year old Rachael Newman whose babysitter is on a date with serial killer, Patrick Bateman. As Bateman begins to dissect her babysitter Rachael breaks out of the duct tape binding her hands and stabs him with an ice pick, which then shows up periodically through the rest of the film. Fast forward to the present day and Rachael is now a college student studying criminology under Professor Starkman, a former FBI agent. Rachael aspires to join the FBI and is hell-bent on getting the teaching assistant position under Starkman, which would make her a shoo-in for the FBI training program.

However, tough competition for the position stands in her way, and Rachael proceeds to kill off classmates. During her killing spree she decides to see the school psychologist, Dr. Eric Daniels. Realizing that Rachael is a textbook sociopath, Daniels tries to warn Starkman, who mistakenly thinks the psycho student is Cassandra Blaire with whom he had an extramarital affair. When Cassandra reveals that her affair with Professor Starkman has guaranteed her the TA positions Rachael decides to murder her as well. After she does so Professor Starkman discovers Cassandra's body and calls Daniels to tell him that "she's dead". But he does not identify the victim, and Daniels assumes it must be Rachael. Distraught, Professor Starkman leaves his teaching position, which angers the obsessed Rachael. She reveals that she is not Rachael Newman: she killed the real Rachael at the beginning of the semester and assumed her identity.

During spring break Rachael stays on campus and confronts an inebriated Starkman and tries to seduce him to get the job. She then confesses her crimes to him as he backs up towards the window in a state of confusion and fear. Rachael blows him a kiss, and he falls out, dying. As she leaves she realizes a janitor has witnessed Starkman's death, and she murders the janitor, too. Driving away from campus with Starkman in her car, Rachael gets pulled over by a cop, whom she stabs to death with an ice pick. As the movie reaches its conclusion Daniels and two cops pursue Rachael in a car chase, which ends with Rachael driving off a cliff, and the car exploding.

In the final scene, Dr. Daniels is giving a lecture on Rachael's mind. When he looks up from speaking with a student, he sees Rachael, who hasn't died after all and it is revealed that she has killed off Starkman's last assistant, Elizabeth McGuire and stolen her identity to get into Quantico and also explains that the real Rachael Newman was the one in the car all along.