Plot
One year after the events of Dorm Daze , the Billingsley University sophomores join a Semester-at-Sea Caribbean cruise, where they will perform a murder-mystery play written by Robin for a competition. Booker breaks up with Rachel to pursue other women, only to discover she has already signed up for the trip. Rusty is determined to lose his virginity, while Marla and Lynn have embraced "born-again virgin" status following court-ordered rehab. Pete, now a struggling stoner after losing his financial aid because of Cliff's actions, competes against the successful Gerri for a student grant. Dante, who is obsessed with Robin, learns she is having an affair with her professor, Rex Cavendish.
Aboard the ship, Cavendish gives a lecture about the Pharaoh's Heart, a $20 million diamond he secretly stole. During a night ashore, Pete and Wang impulsively buy a kleptomaniac monkey, Choo Choo. Back on the ship, Cavendish unwittingly avoids an attempted poisoning by an unseen killer, though Choo Choo steals the vial of poison. When Cavendish tries to flee the ship with the diamond, he and the killer scuffle: Cavendish falls to his death, and the diamond disappears into the lower decks. Rusty and Foosball find Cavendish's body, mistake him for being drunk, and accidentally cause him to be sent overboard.
The following morning, after a drunken hookup with Stukas, Gerri runs into the dean while sneaking back to her room naked, giving Pete the advantage for the grant. Rusty tries to get her drunk again to seduce her, then stumbles blindly into the women's showers after Marla splashes him with alcohol, ultimately ending up dangling naked outside Newmar's window and publicly ruining Newmar's chance to finally have sex with his devout girlfriend Violet. Embarrassed, Violet quits the play, and Rachel takes her role.
During rehearsals, Rachel and Booker reconcile. Choo Choo uncovers the real diamond and drops it onstage, where it becomes mixed with a chest of prop glass gems. Rusty later realizes that Mrs. Bunkley, the captain's wife, is a former porn actress, and blackmails her for sex, arranging to return during the play. Before the play, Pete spikes Gerri's drink to sabotage her, while Dante, hoping to ruin Robin's work, drugs Stukas with what he believes is a hallucinogenic, unaware Choo Choo has replaced it with the poison.
During the play, Stukas collapses and dies onstage, causing Gerri to drink heavily, though the others assume he is acting. Lynn drops a diamond and it does not break, causing Pete and Marla to realize it is the Pharoah's Heart and chase after it. Rachel and Booker improvise to cover for the missing cast members. Rusty's meeting with Mrs. Bunkley is interrupted by Captain Bunkley, who discovers the room full of naked men. The men flee, chased by the enraged captain.
The play descends into chaos before the naked men run across the stage, followed by the captain, who spots Pete with the diamond. Revealing himself as the killer, he explains that he wants the gem as a gift for his wife, but he is killed when a loose stage light falls on him. The audience cheers, assuming the events are part of the show.
As the ship returns home, the dean disqualifies Pete and Gerri from the grant for misconduct. Although the troupe wins the competition, he denies Robin the award since the play performed was not her script, while Dante faces potential prosecution for unintentionally killing Stukas. When the diamond drops and shatters, the students realise it is another fake. Rusty joins a queue of men waiting to have sex with Mrs. Bunkley, while Violet takes pity on Newmar and has sex with him. Elsewhere, Choo Choo triumphantly keeps the real diamond.
