S3, E25: The end of senior year is finally here, bringing the excitement of graduation and the anticipation of new lives in college and beyond. But for Seth, Ryan, Marissa and Summer, it's also a time to look back on the amazing journey that has brought the four of them this far. Seth must confront his recent misdeeds or deal with the wrath of Sandy--and the police. Ryan's proud mom arrives with a surprise for him. Marissa receives an astounding proposal that may radically change her plans. And Summer, facing the prospect of going away without Seth, can't stop crying and hugging her best friends as they say their farewells. Kaitlin (recurring guest star WILLA HOLLAND) returns and moves into Julie's home, vowing to become the next Cooper to rule Harbor High. And to Taylor's (recurring guest star AUTUMN REESER) joy, the "core four" turns into the "fab five." However, although the kids may be ready to move on to bright futures, unresolved issues from their past could ruin everything.