'90210' Season 1 Episode Guide

Annie and Naomi's heated argument gets put on hold as they try to deal with the arrival of their half brother Sean. Harry immediately welcomes his "son" with open arms and invites him to move in with the family.

Silver gets jealous when a cheerleader appears to show an interest in Dixon, who is feeling like an outsider now that Sean is in the picture.

Kelly and Brenda's relationship gets progressively worse when Brenda reveals that she slept with Ryan after the fashion show. Some things just never change with these two!

Naomi makes some new friends, who make it clear their friendship is on a conditional basis.

Naomi and Annie battle it out over who spends the most time with Sean. Although the family seems to be getting along well with Sean, Annie is put off when she overhears Sean on the phone. Her suspicions are further raised when Sean tells Harry that he must come up with a large sum of money or he'll be killed.

Adrianna invites Brenda to support day at her rehab, however Adrianna's world is turned completely upside down when she learns that she is pregnant!

Dixon and Christina's (the cheerleader) friendship grows and she invites him to attend a big party that includes big names from the music industry -- an invite Dixon fails to mention to Silver.

Annie's suspicions ring true when Harry discovers that Sean was a fraud.

Debbie is furious when Tabitha buys the kids a car without discussing it with her first. Annie and Ethan take a trip to Tabitha's house in Palm Springs with full the intention to take their relationship to the next level (which doesn't happen).

Adrianna tells Naomi about her pregnancy and the two become BFFs again. However, things don't go as smoothly between her and Navid when she fills him in on her condition.

Dixon and Silver's relationship takes an interesting turn when he says, "I love you."

After learning that Tabitha encouraged Annie to go to Palm Springs, Harry and Debbie hightail it up there, only to find Annie and Ethan sleeping in separate rooms.

Kelly and Naomi stand by Adrianna as she deals with her situation. They encourage her to reveal the baby's father, who turns out to be Ty!

Annie and Ethan practice for her audition. Ethan agrees to try out for the play so the two can spend more time together -- and after learning that Ty would be auditioning as well. She is deeply disappointed when Adrianna gets the lead.

Dixon goes to Debbie for relationship advice when things get complicated with Silver. He ultimately decides to break up with her.

Ethan is involved in a car accident while on the phone with Annie.

Adrianna tells Ty that she's pregnant, and he's the father. Once he gets over his initial shock, Ty tells her he's there for her and that his parents will be as well. Although she still hasn't broken the news to her mother, Adrianna meets with Ty's parents, who immediately take charge of the situation.

Ethan connects with Rhonda, the girl he injured in the car accident. As they get to know each other better, Ethan realizes that he has been living in a bubble his whole life, so he begins to live life outside his comfort level.

Dixon and Silver argue, but finally make up and get back together.

When Ty's mother oversteps her boundaries, Adrianna's mother gets involved. Surprisingly, she handles the pregnancy news better than expected.

It's Valentine's Day and love is in the air!

The new generation's Dylan McKay comes to 90210 in the form of Liam, a mysterious bartender Naomi meets at the hotel. The sparks instantly fly between these two.

Ethan and Annie's relationship hits the skids when he begins to spend more time with Rhonda. Annie sinks to Naomi's level by getting dirt on Rhonda to use against her, but it backfires in a bad way.

Dixon and Silver's romantic night doesn't go as planned, but it turns out for the best in the long run.

Adrianna settles in for a night with only chocolate to keep her company, but the night takes a turn for the better when she gets a surprise visitor.

Naomi continues to pursue Liam and offers to be his math tutor in a desperate attempt to get some time alone with the hunk. When Liam takes her on wild night of drag racing, will her obsession turn to terror, or turn her on that much more? Is Silver losing her mind? That is the general consensus when a video assignment turns into a scary/obsessive love story featuring Dixon. Annie and Ethan's relationship hits the skids when Adrianna reveals that she saw Ethan and Rhonda kissing.

In this Jason Priestley directed episode, Ryan and Kelly go in search of Silver. Their search brings them to Kelly's mother's home, where the two women share a heated exchange. Dixon tells his parents what has happened with Silver and they are none too pleased. Annie and Ethan's relationship continues to crumble. Adrianna and Navid try their hand at parenting when they babysit Kelly's son -- and they are surprised at how natural it comes to them.

Donna Martin returns! Donna pays Kelly a visit from Japan, and we learn that all is not well between she and David. Diablo Cody (who appears in this episode) asks Donna to design a dress for her to wear on the red carpet. Dixon and Annie take a road trip to visit his biological mother. Ethan spends his spring break volunteering with Habitat for Humanity. When Liam joins the cause as well, Naomi signs up so she can spend some time with her new obsession -- and it's not exactly going to go very well.

Donna is faced with a difficult decision -- should she return to David in Japan, leave him for good and move back to Beverly Hills for her fashion career? Liam continues to be a bad influence over Ethan. Adrianna and Navid interview prospective adoptive parents for her baby. Annie and Naomi decide to become friends again.