Sam and Josh have an embarrassing encounter during a play rehearsal, starting rumors that they are interested in each other. Meanwhile, Brooke confesses to Nicole that she and Josh are still virgins, and Harrison's hope for a relationship with Brooke gets a boost when she turns to him for comfort.

Brooke and Sam are forced to hold their annual Christmas parties together, and Carmen is injured just weeks before the next round of cheerleader tryouts. Meanwhile, Nicole's brooding over the yuletide season leads to visits from the ghosts of Christmas past, present and future.

Sam gets a chance to produce a segment on a syndicated TV show--with one catch--Brooke is the on-air talent. Meanwhile, Josh must tell his father that he can't make a dinner with college scouts, which is scheduled for the opening night of the musical; and April Tuna becomes obsessed with Carmen.

Mounting tensions between Sam's friends and Brooke's clique lead to a proposed rumble, but the guys intervene and lock the ladies in a school bathroom in an attempt to make them reconcile. Meanwhile, Josh, Harrison and Sugar Daddy get an education on ovulation from a nature film provided by Bobbi Glass.

Nicole is desperate to save her popularity, which is falling since she was banned from the Glamazons. She tells Brooke that she should dump Josh and start dating George. Harrison is feeling a little bit jealous about Sam and George flirting, and so he and Nicole team up to make a study on attraction for chemistry class. Brooke and Josh break up. Sam feels like she lost again to Brooke when she sees she and George together. But George tells Sam he is really into her and they kiss. Josh and Lily find themselves attracted to each other when he helps her to send a gay chimp back to his lover in Uganda. Harrison learns more about Mary Cherry and starts to have feelings for her (could it be love?). Jane tells Mike she's pregnant.

Ms. Glass wants all the students to write down where did they go for Spring Break and how many they slept with, so, in her own words, she can judge them. Most of the gang say they went to Cancun, and Harrison writes that he went to Yemen as his nose starts to bleed. Ms. Glass deduces he has been infected with the Rift Valley fever that is contaminating everyone in Yemen. Just as Sam was trying to talk to him by his locker, they are both isolated from the rest of the people and the school is shut down in quarantine. During Chemistry, Mary Cherry receives a call in her cell phone from someone who knows what she really did for Spring Break - a low-budget soft porn scary movie - and she has to run for her life as she is chased to be killed. Meanwhile, Lily tells April what they really did for SB. They intended to go to Cancun, but they all stayed in LA and had SB in different ways. Nicole is elected to attract the killer, but since she's not a virgin, and only virgins get chased by killers