Season Four: 2011–12
The fourth season begins with Naomi breaking up with Max after what she feels is his excessive relief on discovering that her pregnancy was a false positive.
At the end of the summer, the various kids are preparing to move on with their lives. Liam comes back from his job on the fishing boat and asks Annie twice to marry him; she says no both times. Liam drunkenly buys a beach bar and starts to develop feelings for a widow he met over the summer. Silver and Navid are living together as Navid manages his business, but are forced to take in his rebellious teenage sister, Leila (Summer Bishil), when she refuses to go to boarding school. His life is complicated by Leila's rebellious nature and by the discovery that his uncle has been running a stolen car ring out of Shirazi Studios. Ivy finds herself dealing with the emotional toll from Raj's deteriorating health. Naomi, attempting to make a big impression at CU buys a large house, coming into conflict with the owner's son Austin (Justin Deeley), who had been growing marijuana on the property. Naomi throws a big elaborate beginning of school party for CU students but this backfires when the party is raided by the police and Naomi disposes of Austin's marijuana plants by tossing them on a bonfire, causing CU's star quarterback to later test positive for drug use. The disastrous party causes Naomi to enter CU as the most unpopular girl in school, a situation she attempts to rectify by pledging a popular sorority. Initially, things appear to be going well as Naomi is taken under the wing of the sorority President, Holly (Megalyn Echikunwoke). But after performing a series of humiliating hazing rituals, Naomi discovers that Holly never intended to let her into the sorority and that this was all done to humiliate Naomi. Vowing revenge, Naomi buys her way into the only sorority that will have her: one made up of nerds and social rejects, and becomes their president. Naomi has sex with Austin after he agrees to help her new sorority humiliate Holly. However, she later learns that Austin was using her to break up with Holly, whom he had been dating. When Holly invites Max to a campus event to unsettle Naomi, she rekindles her romance with him, but still finds herself attracted to Austin. Naomi later ends up with Austin and she and Holly become short-lived friends. After Naomi gets the internship that Holly wanted, Holly retaliates by attempting to sleep with Austin. Hurt, Naomi breaks up with Austin. Annie finally gets her inheritance when she records Jeremy calling Marla a bitch. Liam gets into a motorcycling accident after trying to find Annie. A blonde-haired woman named Vanessa, who hits Liam with her car, calls 911 and says that it was a "hit and run". When the winter premiere begins, Liam has been hanging out with Vanessa as she has been trying to create Liam into a star by managing his career. Annie and Dixon return from Paris after spending Annie's new-found wealth. Silver finds out by the end of the episode that her boyfriend's adopted daughter might be Adrianna's. Dixon has a mild stroke and is taken to the hospital. The doctor inform him that he need to avoid stress, but he's been under pressure of hiding his newfound success with his music career sans Adrianna. Liam consoles Silver who learns that she may have the cancer gene that caused her mother's death two years ago. Upon being discharged from the hospital, Dixon notices Ivy's husband Raj has been admitted to the same hospital and learns that Raj's cancer fail remission and is dying. However, Raj tells Dixon not to tell Ivy but disagrees with his wishes and breaks the bad news to Ivy. Ivy visits the hospital, along with the support of her friends, and makes amends with Raj. As she returns to Raj's room, she learns that he had passed on and dies in his sleep. Naomi's sister Jen makes an unexpected visit, and her arrival sparks yet another falling out between the two sisters. This time, the sisters fight over the affections of Preston "P.J." Hillingsbrook, a playboy with a lot of cash to blow as the heir to his family’s fortune. When he reveals that it was Naomi that he was originally infatuated with, Jen does another disappearing act and returns to Paris but not before revealing to Naomi that P.J. was involved in a scandal. At Raj's funeral, the record company calls Dixon's phone, which Adrianna had in her possession and she finds out that they've signed him but not her. Navid comes back for the funeral, and the gang pays their final respects for Raj at the beach. Meanwhile, Liam and Vanessa break up over her attitude towards Silver. She then steals all the money from the bar. Silver learns that she is positive for the cancer gene and cries on Liam's shoulder. The two kiss and sleep together. Ivy is seen late at night at the beach with her surf board. Caleb who is at the beach warns her about the danger of surfing in the rough waves but Ivy heads on muttering to herself "Nothing lasts forever right" and runs into the water.
Later, the scandal behind P.J. is that in order to receive his trust fund he must marry before he turns 28 years old, and so he proposes to Naomi, unbeknownst to her. Annie finds out about the clause and tells P.J. to come clean to Naomi, which he reluctantly does. As Naomi learns the truth, she breaks off the engagement. Whilst Dixon is away, Austin returns to town and proposes that Adrianna should start a country music career with his help. Adrianna accepts his offer as Austin becomes her manager, but Austin also has his eyes set on steering Adrianna away from Dixon. Navid also returns and reveals that he wants to resume his relationship with Silver who has found out she has the cancer gene. This causes a dramatic turn as both Liam and Navid want to be with Silver. A fight breaks out between Liam and Navid during the premiere of Liam's new movie. As a result, Silver decides to side with Navid. Meanwhile, Naomi is the event planner for a young woman named Madison who is enthused by her upcoming nuptials. Naomi gets the shock of her life when she learns that the groom-to-be is none other than Max, her ex-boyfriend. At the bachelor's party, Max questions Naomi asking her if he is doing the right thing and before she can reply is interrupted by Max's fiancé. During the rehearsal wedding, Holly's mother comes back into play and offers Naomi a job offer that she can not refuse. Naomi takes the offer but at the airport is talked out of it by Austin because she is still in love with Max. As the wedding of Madison and Max begins, Naomi abruptly interrupts the services and confesses her love for Max. Elsewhere, Ivy is seen going off to Mexico to be with Diego, who was deported because he was an illegal immigrant in the U.S., and only ask for a one-way ticket. Annie and Caleb break off their relationship because Caleb can not leave the covenant for Annie. Navid reveals that he isn't ready to have a baby which causes Silver to dump him. She still wants to conceive a child and proposes to have a baby...with Teddy. At the very end of the season finale, Adrianna is boarding a plane to Las Vegas to kick start her country music career because Dixon has not returned on time from the tour but little does she know the car broke down and he had to hitch hike. As Dixon is on the phone with Navid telling him to stop Adrianna, a truck hits Dixon's car and it is left unknown if Dixon is still alive.