|← S3||The OC Season 4|
|#01||"The Avengers"||#7||"The Chrismukk-huh?"||#13||"The Case of the Franks"|
|#02||"The Gringos"||#8||"The Earth Girls Are Easy"||#14||"The Shake Up"|
|#03||"The Cold Turkey"||#9||"The My Two Dads"||#15||"The Night Moves"|
|#04||"The Metamorphosis"||#10||"The French Connection"||#16||"The End's Not Near, It's Here"|
|#05||"The Sleeping Beauty"||#11||"The Dream Lover"|
|#06||"The Summer Bummer"||#12||"The Groundhog Day"|
Summer soul-searches during a visit from Seth. Taylor pleads for Ryan's help with her marriage. Sandy longs for a guys' night. Julie vows to turn over a new leaf in moving on from Marissa's death.
Summer is in counseling to manage her grief over Marissa's death. (She moves through the five stages of grief in a 30 second montage of one week's sessions.)
When Seth comes to Providence to visit her, she tries to go back to her old carefree, fun-loving self. But the last few months at Brown as a social activist have changed her personality permanently.
After a day of shopping at the mall, it's clear that Summer doesn't find such frivolous activity as rewarding as in the past. She is drawn back to her new friends and their most recent worthy cause. Seth worries about whether or not he fits into her new life, her "go-GREEN phase", but she assures him that she still loves him. He encourages her to follow her new calling and takes off for home ahead of schedule.Sandy realizes he has no male friends left and tries to change that by awkwardly asking Jason 'Spitzy' Spitz to hang out. Their attempt to play golf is hampered by their ringing cell phones. They end up at a bar, drinking beers and watching a game. He takes a phone call from Kirsten and ends up going home to be with her.
After the break-up with Neil, Julie makes a bet with Kaitlin: Julie stays away from men, Kaitlin from trouble. Taylor joins them in the kitchen, mentioning how much she likes staying in Summer's room and "how did she ever live without a home gym?" Kirsten and Julie begin plans to go back into business together. Julie and Kaitlin's wager doesn't work out so well and they both end up in a club, where Julie is dancing wildly with a younger man and "Newpsie" friend Taryn Baker, while Kaitlin used a fake ID to get in (Eric and Brad Ward are denied entry by the door man).
Taylor asks Ryan to help her to get out of her marriage with Henri-Michel from France. Due to a French law, Taylor has to prove her infidelity. At first Ryan refuses to get involved, but eventually comes to her rescue by kissing her in front of Henri-Michel's lawyer. Taylor gets her divorce and is obviously swept off her feet. Later in the evening, she surprises Ryan in the pool house with a home-made peach torte as a thank you gift. As she leaves, it is clear she has developed feelings for him.
- Melinda Clarke as Julie Cooper-Nichol
- Peter Gallagher as Sanford "Sandy" Cohen
- Rachel Bilson as Summer Roberts
- Kelly Rowan as Kirsten Cohen
- Autumn Reeser as Taylor Townsend
- Adam Brody as Seth Cohen
- Willa Holland as Kaitlin Cooper
- Chris Pratt as Che Cook
- Kim Oja as Taryn Baker
- Jose Zuniga as Jason Spitz
- Wayne Daglish as Brad Ward
- Corey Price as Eric Ward