Marissa discovers something in Johnny that Ryan lacks and Charlotte convinces Julie and Kirsten to throw a charity event. After discovering fake IDs in Charlotte's purse, Julie confronts her.

When the gang heads to The Bait Shop to see The Subways, Taylor's horsing around causes a major rift between Seth and Summer. Marissa, determined to end the potentially explosive rift between Ryan and Volchok, does whatever it takes to watch out for Ryan. Meanwhile, Matt, Sandy's Newport Group partner, goes above and beyond the call of duty when he learns he has to cut Newport Group staff.

Marissa visits Johnny at his house after his accident to see how he is doing. Julie and Kirsten get a contract for their new catering business while Sandy, Ryan and Matt meet with investors.

Ryan, Seth and Summer launch a campaign to get Marissa back into Harbour. With the help of Dr. Kim they get the board of trustees to hear the case will Marissa be permitted to return for her final semester?

Kaitlin starts going out with Johnny with the sole motive of making Marissa jealous. Seth starts getting nostalgic as he prepares for his Brown interview.

Sandy and Matt's hospital project hits a roadblock. Kirsten and Julie run into troubles of their own with their matchmaking business. Marissa confesses her feelings to Johnny. Summer finds out out about Seth.

Kaitlin prepares herself to head back to school. Ryan has doubts about his relationship with Marissa after helping out Sadie. Kirsten and Julie make plans for a Valentine's Day party.

When Ryan and Sadie go on a road trip to search for one of Johnny's relatives they end up in Ryan's old neighborhood in Chino, which brings the two closer together. While the two are away Marissa is implicated in Johnny's death and Seth and Summer learn the truth about Julie and Dr. Roberts new secret.

Ryan thinks about not inviting Marissa to his 18th birthday after their falling out but Sandy tries to get him to invite a relative. After months of avoiding telling Summer and Marissa the truth Neil and Julie tell Summer and Marissa the truth.

When an old friend returns to Newport, Ryan decides to help her, which causes problems for him and Sadie. When Summer and Seth run into another rough patch Taylor tries to help them out. Sandy has to deal with more problems with the Newport Group and Marissa must deal with being alone.

Julie and Dr. Roberts announce their engagement and the Cooper ladies move in with Summer and her dad. Meanwhile, Marissa drifts away from the group and Summer when she seeks solace in the bad company of Volchok and his crew. Ryan tries to move on with Sadie, but Seth's concerns for Marissa get in the way. At the Newport Group, Sandy's woes with Matt continue and Kirsten surprises Seth with a night out.

When college acceptance and rejection letters are received the kids must consider what path they are going to follow. Ryan and Sadie are trying to decide what they will do after high school. Taylor holds a college party and Summer and Marissa fix their friendship problems.

Ryan decides to go and invite his mother to his graduation party. Taylor and Summer work together to try and find out what Seth is hiding, but Summer ends up getting hurt. Marissa realises she is in bad company after she finds out how low Volchok's friends can go. Sandy is able to fix his work problems with Matt but while doing so he hurts Kirsten.