Julie and Dr. Roberts (recurring guest star MICHAEL NOURI) announce their engagement, and the Cooper ladies move in with Summer and her dad. Meanwhile, Marissa drifts away from Summer and the group when she seeks solace in the company of bad boy Volchok (recurring guest star CAM GIGANDET) and his crew. Ryan tries to move on with Sadie (recurring guest star NIKKI REED), but Seth's concern for Marissa gets in the way. At the Newport Group, Sandy's woes with Matt (recurring guest star JEFF HEPHNER) continue. And Kirsten surprises Seth with a night out.