FEELING VULNERABLE — When Dorrit (Stefania Owen) goes missing under Carrie's (AnnaSophia Robb) watch, Carrie lashes out at Sebastian (Austin Butler), the one person who can help her find Dorrit. Mouse (Ellen Wong) butts heads with West (guest star RJ Brown), a popular jock who, much to her chagrin, stole her spot as number one in the class. Walt (Brendan Dooling) surprises himself when he confides in someone completely unexpected. Meanwhile, Tom (Matt Letscher) finds himself in uncharted territory when it comes to women and turns to Larissa (Freema Agyeman) for advice. Chloe Bridges also stars. Janice Cooke directed the episode written by Amy B. Harris.