After making an enemy in sorority president Holly, Naomi finds unusual allies who help her get revenge. Annie, short on money for sorority dues, must figure out a quick way to come up with the cash.
In an effort to re-gain her status, Naomi rushes a popular sorority, where she, along with Annie go through sorority games. Annie finds out a shocking secret about new guy Jeremy that could affect her future.
In the season four premiere, the gang from Beverly Hills have graduated from high school. Naomi has spent the summer dealing with the shocking news of her pregnancy and quickly discovers she doesn't have the status at college that she did in high school.
The fourth season of 90210 follows the group from West Beverly as they navigate life after high school. Their journey into adulthood will find them heading in different directions while trying to keep the same closeness that worked so well for them in high school. Some will attend college, while others will start their careers. It's a new and different time for them, as the stakes are much higher and there is a lot more to lose. Coming from a world of glamor and privilege, with endless possibilities in front of them, anything can happen. All in all, it's just another day in the world's most famous zip code.
Naomi makes a decision that could impact her future. Liam makes a revelation to Annie. Ryan asks Debbie to move to Paris. Adrianna is shunned after her scheme is revealed.
As the gang gears up for prom, Dixon and Annie find out some devastating news about their futures, while Ivy learns that Raj's health has taken a turn for the worse. While Silver is in the hospital, Adrianna tries to rekindle her romance with Navid.
Annie convinces Marla to attend a Hollywood movie premiere of one of Marla's old films, while Ryan has an unexpected visitor and Teddy catches Marco in a lie and begins to wonder if he is being cheated on.
Naomi, sick of hiding her relationship with Max and afraid he might be cheating on her, follows him to an academic decathlon event, to confront him. Silver begins to behave erratically, which worries Navid and secretly pleases Adrianna.
When the group decides to take a vacation to Mexico for a much needed break, chaos ensues. Naomi brings her crush Max along, under the guise that she needs extra tutoring.
Dixon and Navid formalize their partnership, and a chance meeting with Snoop Dogg could mean good news for Shirazi Studios. Naomi tries to impress Max by dressing up in an Avatar costume, but doesn't quite get the reaction she was hoping for.
Back to her old tricks, Emily messes with Annie's internship at the playhouse - and with Annie's boyfriend. Silver convinces Navid to sign the release for Adrianna's reality show to help distract her and throw her off the track.
Navid and Dixon convince a music producer to shoot a music video at Shirazi Studios. Adrianna's suspicions are confirmed, and she tells Silver about her plot for revenge.
Everything changes for Navid when he learns how Adrianna used the baby she gave up for adoption. Adrianna leans on Silver for support and makes a shocking discovery.
Naomi, Adrianna, Silver and Annie decide to have a girls' weekend and head to a yoga retreat in Ojai. Annie attempts to be a good cousin and invites Emily along for the weekend but confronts her about being a downer on the trip.
Naomi is taken hostage in her own home by an out-of-control Mr. Cannon who also lures Silver into the situation. Annie and Dixon's cousin Emily from Kansas comes to town for an extended visit, but Emily immediately gets on Annie's nerves.
Adrianna rents a mansion and decides to throw a housewarming party complete with an ice skating rink and elves. All is great in Adrianna's world until Victor decides to reveal Adrianna's secrets to the media.