The summer is officially over, & it's the first day of school. Summer (recurring guest star RACHEL BILSON) still ignores Seth in public, but privately she is jealous of Seth's burgeoning relationship with iconoclastic East Coast girl Anna Stern (recurring guest star SAMAIRE ARMSTRONG). & Summer isn't the only person fighting feelings of jealousy. Kirsten still isn't comfortable with Sandy's friendship with his sexy new co-worker, Rachel (recurring guest star BONNIE SOMERVILLE). Rachel makes matters worse when she specifically enlists Sandy to work on a lawsuit that an environmental group has initiated against Kirsten's father & his land development company, despite the obvious conflict of interest. Kirsten is incensed, but conflicted Sandy truly believes in the environmentalists' cause.