Chaos reigns in the Cohen kitchen as Sandy, Ryan and Seth continue to cope with Kirsten's rehab. When Sandy encourages Kirsten to come home to her family, Kirsten's attachment to Charlotte (recurring guest star JERI RYAN) raises concern in Sandy. Meanwhile, at The Harbor School, Dean Hess (recurring guest star ERIC MABIUS - "Eyes"), the new Dean of Discipline, arrives and makes a decision that changes Marissa's life forever. Summer trumps her cardigan-wearing, goody two-shoes nemesis Taylor Townsend (recurring guest star AUTUMN REESER) when planning the annual Kick-Off Carnival. And Jimmy (recurring guest star TATE DONOVAN) offers Julie a surprising proposal.