The Wilson family arrives in Beverly Hills, after Harrison "Harry" Wilson takes a job as the principal at West Beverly High School, while his children, Annie and Dixon, attend the school during their first week much to the awkward circumstances of their father watching over them, while Harry and his photographer wife, Debbie, also keep a close eye on Harry's washed-up, alcoholic, actress mother, Tabitha. For Annie and Dixon, the school is one big culture shock for Annie, a sweet and friendly girl with a passion for the theater, and Dixon, a star athlete and scholar who was adopted by the Wilson family after they took him in as a foster child. Annie and Dixon have a close sibling relationship, which they'll need to help them cope with all the new cliques and classmates, including Naomi Clark, a hot and stereotypical spoiled rich girl who believes that money buys everything; Ethan Ward, Annie's former boyfriend from Kansas who's now Naomi's boyfriend, and a popular lacrosse star whose abilities rival Dixon's; Navid Shirazi, an aspiring student reporter who heads up the school's daily TV newscast; and Erin Silver, a rebel and wanna-be socialite who produces and stars in a YouTube-type video series, and who develops a crush on Dixon. Adrianna is a fellow student and theater "goddess" who is Naomi Clark's best friend... and Ethan Ward's secret girlfriend, and who has a serious drug addiction; George Evans is an arrogant West Beverly High student, who takes an instant dislike to Dixon because of his race (Dixon is black). Wendy is "sexy vixen" student at West Beverly Hills High who takes every advantage of her looks; Ty Collins is another student and theater major. Even the faculty seems hip and sophisticated at the school whom include the smart and funny teacher Ryan Matthews, beautiful guidance counselor Kelly Taylor, and successful theater actress-turned-high school-musical director Brenda Walsh. The Wilson family has just begun to realize how much their lives are about to change.

Dixon and Annie find their Friday night plans disrupted after Debbie and Harry plan a family bowling night without consulting them. So, Annie plans to sneak out of the place to meet with Ty to attend a rock concert, while Dixon plans with Navid and Ethan to sneak him out so they can watch a movie at Navid's house. Meanwhile, Naomi has an unpleasant evening with her estranged and selfish businessman father, Charles, who puts her off for work. Also, Dixon invites Silver over to the Lucky Strike Bowling Alley, and he later finds Silver asleep in his car. Silver then confides in Dixon about her troubled home life and how her drunkard mother, Jackie, verbally and physically abuses her. The news gets back to Kelly who confronts Jackie about it, while at the same time, Kelly continues to be sought after by Ryan who tries asking her out on a date.

Annie and her parents, Harry and Debbie, are surprised to learn that West Beverly's theater director can no longer oversee the school musical. Tabitha offers to direct the musical play, but her eccentric and demanding attitude does not sit well with Annie or the other actresses. Kelly persuades Brenda to take over as the play's director, much to Tabitha's chagrin. But Kelly and Brenda end up continuing to argue over Kelly's continuing involvement with Ryan and taking up time with Kelly's son, Sammy. Meanwhile, Dixon tries to get a part time job at the Peach Pit coffee shop to get money to pay off a bully after Dixon accidentally dents the bully's car. Naomi becomes more distraught over her parents, Tracy and Charlie's, open-marriage arrangement, and she eventually confronts her father's mistress to show her true anger towards her. Elsewhere, Annie's growing relationship with Ty is the talk of the school, which leads to Ethan, who's growing more uncomfortable and jealous, to try to get her attention.

As opening night for the school play nears, Harry catches Annie kissing Ty, which makes him worry that she and Ty are moving too fast with their growing romance. Silver, stressed out from her job as the stage manager, gets some comfort from Dixon. Meanwhile, Naomi tries make her mother and father get back together, but Tracy's mind to divorce Charlie is made up. On the opening night of the play, the star Adrianna's drug use comes to surface from being under constant pressure from her overbearing mother, Constance, and when Brenda discovers this, she replaces Adrianna with Annie in the lead alongside Ty. But when both Brenda and Kelly confide in Constance about her daughter's drug abuse, Constance (a secret drug abuser-in-denial herself) refuses to believe them. Afterwards, Adrianna successfully gets her revenge when she manipulates and breaks up Ty and Annie's romantic get-together at a celebration party at a local hotel.

Adrianna and her evil-witch-mother, Constance, plot a cruel revenge against Annie and the rest of the faculty at West Beverly whom they think cheated Adrianna out of her role in the school play. Debbie's boss, Antonio, offers her a job to shoot a fashion show for Nylon Magazine during Fashion Week, where Annie uses the opportunity to her advantage for a class assignment, while her father advices her to try to make amends meet with Adrianna in order to try to catch her in the act with her substance abuse. Naomi believes the upcoming fashion show could help her parents' marital problems and she plans with Ethan to try to break up her father and mistress and have her mother, Tracy, meet with Charles, but it only makes matters worse. Ty and Annie's relationship is put to the test because of Adrianna's meddling. But when Adrianna lets her guard down and reveals to Annie that she lied about hooking up with Ty to break them up, it results in Annie declaring war. Silver is pursued by Debbie's sleazy client, Tony, to work in modeling, while a jealous Dixon becomes aware about what's going on, while Navid feels like he's the 'third wheel' to Dixon and Silver's growing romance. Meanwhile, Kelly receives a phone call from Sammy's father that could change her relationship with Ryan when she's offered to move to Wyoming to join Dylan, while Brenda, with her work at West Beverly finished, plans to return to New York.

As Silver's "half birthday" approaches, she decides to spend a spooky evening by watching horror movies with her friends at the famous Hollywood Forever Cemetery. But Dixon is not eager to attend when he reveals to her that he does not watch horror films. Meanwhile, Harry's past returns to haunt him when Tracy reveals she is searching for their long-lost illegitimate son. Annie and Ethan are paired up for an assignment, which leads to a possible romantic connection after the two take care of a baby. A mysterious new student, named Kimberly MacIntyre, arrives at West Beverly which considers with a police raid on the school searching for narcotics which leads Naomi to cover for Adrianna when Naomi takes the fall by taking her cocaine stash. After Naomi confronts Adrianna over her escalating drug addiction, she agrees to come forward to clear Naomi, but Adrianna soon goes back on her word when she lands another acting role which could jump-start her acting career and make her difficult-to-please mother proud. Also, Ryan seeks to explore his horizons since his breakup with Kelly by dating an attractive, but dim-witted actress.

After spending several days in the hospital recovering from a near-fatal drug overdose, Adrianna tries to make amends with Naomi. But Naomi refuses to forgive Adrianna for her betrayal. While serving her detention, Naomi meets a trouble-making punk, named Ozzie, who could spell trouble for her. Later, Adrianna makes a connection with Navid, who helps her through her situation as she's accepted into a rehab clinic. Meanwhile, Annie and Ethan finally take their rapidly growing romance to a new level during the school's annual homecoming dance, causing Naomi to feel jealous. Dixon asks Silver to the dance, but she turns him down for she feels, in her liberal and radical mind, that Homcomming is the scene of the morally corrupt. Ryan believes that the new student, Kimberly, is a narc after he sees her purchasing drugs. Also, Debbie confronts Tracy about the time Tracy kissed Harry.

Harry and Debbie welcome Sean into their home, while Dixon, Annie, and Tabatha welcome him awkwardly despite the fact that they don't know much about him, while Naomi and her mother, Tracy, welcome him to their home as well. Meanwhile, Kelly and Brenda's friendship is slowly fading away and gets wider after Brenda is hospitalized from an accident and confides in Kelly that she seduced Ryan weeks earlier. Naomi decides to hang out with a new group of girls at school despite Ozzie's advice that they want nothing to do with her. Also, Silver feels threatened when a cheerleader, named Christina, shows too much interest in Dixon who shares the same interests he does.

Annie overhears Sean in a suspicious conversation with someone over the phone, which raises her uncertainty about whether Sean really is who he claims to be. Meanwhile, Brenda tries to make amends meet to Kelly after confessing about a tryst she had with the departed Ryan Matthews. But Kelly and Brenda have to team up to accompany Adrianna to a group therapy session for recovering addicts where after she learns that a friend of hers is HIV-positive, Adrianna goes to a clinic to get tested, but receives some other potentially life-changing news. Elsewhere, Christina invites Dixon over at her house for a Gospel gathering where she makes a startling revelation to him which could shake his romance with Silver.

Naomi and Adrianna take a road trip along the California coast to get away from their respective life problems, but more complications set in when their money and clothes get stolen from Naomi's car, including her wedding ring which prompts them to venture to a seedy biker bar to find their culprits, where Adrianna hooks up with a young motorcyclist and Naomi ventures to visit her estranged mother. Meanwhile, Liam finds himself held captive by the deranged Ashley in the basement of Offshore who has plans to take him to Mexico, while Annie and Vanessa learn that Ashley is not who she says she is. Dixon prepares a party at Naomi's house to celebrate the opening of his new recording label. Megan tells Dixon that she feels that he is not over Adrianna, so in order to move on, Dixon decides to let go of his anger and not feel anything for Adrianna. Elsewhere, Silver is still having problems with Teddy about the impregnation when he continues to want to be a part of her baby's life, while she wants to raise her child alone. Silver goes to Teddy's uncle to persuade him to drop his attempts to block her procedure, but when Teddy still will not back down, a row occurs which makes things worse for everyone.