The Undertow

S3, E18: When an old nemesis returns to Newport, Ryan gets caught up in helping her, causing a rift between him and Sadie (recurring guest star NIKKI REED). Seth and Summer are faced with a new problem that Taylor (recurring guest star AUTUMN REESER) tries to solve. Meanwhile, Marissa finds herself all alone in Newport with no one to turn to, and Sandy grapples with business pressure.