Ryan Atwood has returned to The O.C. 10 years later, now a successful architect, strangely, on the anniversary of Marissa Cooper's death, where family and friends are celebrating Marissa's life. When Ryan reconnects with estranged ex-love, Taylor Townsend, Marissa's sister Kaitlin, sets her eyes on Ryan, to her mother, Julie Cooper's chagrin. When a troubled teen arrives in The O.C. with mysterious connections to Ryan, will it bring Taylor and Ryan closer, or tear them apart?