When Taylor learns about Ryan's sleeping problems she devises a plan to help him but must then turn to Kaitlin when her plan backfires. At Brown Summer and Che step up their activism and it lands them more freedom than imagined. Julie also gets help from Kaitlin to help save the dating service.

Kaitlin takes down the school mean girl by throwing a rager at her house. Sandy and Kirsten find time to bond with Ryan while Seth is away visiting Summer at Brown but all he finds is an empty dorm room. Meanwhile Julie continues work on the dating service and finds out a new surprise.

Ryan and Taylor may be heading out on a Las Vegas road trip for New Year's Eve, but there's even more fun in store when Seth and Summer join them. Meanwhile Julie doesn't trust NewMatch's new accountant, and Sandy suspects the reason why.

Taylor's ex-husband comes to Newport and causes a rift in her relationship with Ryan. Seth goes to Seattle to obtain Dr. Roberts blessing, while Summer "travels to the past" for 48 hours. Kaitlin finds love, while Julie finds problems with Kirsten.

Ryan overcomes his indecision and competes with Henri-Michel for Taylor's affections. Che leads Seth on a trek of spiritual renewal. Meanwhile, Kirsten and Julie have to do some damage control.

The Cohen family says goodbye in the series finale as the episode jumps six months after the earthquake to show the Cohens, Ryan, Taylor, Summer and the Cooper women trying to piece their lives back together. The Cohens find out that fixing up their old mansion would cost more than rebuilding it but Ryan and Seth see this as an opportunity to give Sandy and an expecting Kirsten a surprise that'll change their lives.