Noami grows spiteful as Annie and Ethan grow closer, causing her to deliver an unwelcomed surprise at Annie's sweet 16 party. Meanwhile, the school is all buzzing over the news that Ryan was given a leave of absence, and Adrianna discovers Navid's secret.

Naomi's older sister, Jen, unexpectedly returns to Beverly Hills. Meanwhile, Naomi persuades Annie to go on a double date, and Adrianna and Navid reveal their decision to his parents.

Navid wakes up in the hospital but has no memory of who pushed him down the stairs. Adrianna visits Navid and following her conversation with him, makes a life-changing decision about her addiction to pills. Silver and Teddy bond over the loss of both of their mothers and unexpectedly get close. Liam, Dixon and Ivy learn that Naomi and Jen will be attending the horse races and devise a plan to finally reveal the truth to Naomi about her evil sister. Annie and Jasper sneak out even though Harry and Debbie have grounded her.

Naomi embarrasses herself in front of her boss Rachel in an attempt to get over her break-up with Austin. Dixon and Adrianna are booked to perform at a club, where they realize that working together might be a bad idea. Meanwhile, Silver takes her relationship with Greg to the next level and a party Annie throws ends up being a disaster because she is too distracted by Liam's new relationship.