Kirsten visits Rebecca and though she convinces her to leave, she also learns that Rebecca loves Sandy. Seth frets over whether Summer and Zach had sex. His spirits rise when he learns they didn't, but fall again when he learns it wasn't Summer's decision. When Caleb announces he will officially adopt Lindsay, her mother confesses to Ryan that he should stop her from taking a paternity test because Caleb may not be her father. Alex asks Marissa to invite Summer to hang out with Alex and her friends. Marissa confesses her relationship to Summer after some soul-searching.