When Carrie (AnnaSophia Robb) is invited to a Halloween party in the city by Larissa (Freema Agyman), she decides to invite Walt (Brenden Dooling) to go with her to keep her company. It doesn't take long before the night goes awry and Carrie is forced to babysit Larissa, who has clearly taken too many drugs. Walt finds himself in an uncomfortable position after a party guest gets a little too close for comfort. Elsewhere, Maggie (Katie Findlay) convinces Mouse (Ellen Wong) to go with her to Sebastian's (Austin Butler) Halloween party at the diner to help keep tabs on him. After Doritt's (Stefania Owen) attempt to sneak out of the house is thwarted, she discovers hanging out with her father (Matt Letscher) isn't so bad.