New couple Carrie and Sebastian can't seem to catch a break. Between being grounded and rival Donna's sneaky attempts to break them apart, Carrie worries Sebastian will lose interest in her. Desperate for some alone time with him, Carrie must lie to her father and bail on plans with her sister Doritt Maggie's obsession with having sex drives a wedge between her and Walt Meanwhile, Larissa wants to do a photo shoot with Carrie's purse for Interview magazine forcing Carrie to scramble to make it work.

After Tom forbids Carrie to see Sebastian again, Carrie snoops through Tom's work files and uncovers some alarming information about Sebastian's past. Carrie decides to confront Sebastian about what she's discovered and is shocked by his reaction. Maggie deals with her breakup with Walt in the only way she knows how and finds some solace from Dorrit Meanwhile, Larissa takes Carrie, Mouse and Seth to an outrageous performance art club in New York City, which leaves them all feeling self-conscious.

When Carrie is invited to a Halloween party in the city by Larissa, she decides to invite Walt 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 convinces Mouse to go with her to Sebastian’s Halloween party at the diner to help keep tabs on him. After Doritt’s attempt to sneak out of the house is thwarted, she discovers hanging out with her father isn’t so bad.

Carrie runs into an old friend at her internship and gets invited to his mother's dinner soiree in Manhattan, but her feelings for Sebastian get in her way, until she see him with another girl. Mouse is excited about getting back together with Seth, but her worries about being bad at sex drive her to ask Walt for help. In order to hang on to a favorite spot at the diner, Maggie takes on Donna LaDonna and her friends. Meanwhile, Tom loses his wedding ring, which makes him realize that Harlan might be right about starting to date again.

Carrie gets in way over her head when she tries to cook the perfect Thanksgiving dinner for her family, her new boyfriend George and his dad Harlan, so she enlists Mouse's help. Tom is oblivious to the chaos going on in the kitchen, while Dorrit finds a new way to torture Carrie. Maggie is excited to have Thanksgiving with Walt's family, but when the topic of college comes up she realizes that she hasn't put much thought into her future. Elsewhere, Sebastian learns that his mother decided to fly out of town with her boyfriend, leaving him to fend for himself on Thanksgiving.

Impressed with Carrie's creative prowess, Larissa offers her an internship at Interview, but Carrie is torn about whether she should take it. Carrie invites George to the school dance, but when she suggests they leave the dance early, George gets the wrong idea about her intentions. Dorrit, who used to go to the Nutcracker ballet with her mother every year, reluctantly agrees to go with Tom, but he has a hard time filling his wife's shoes. Mouse gets a B+ on an exam and blames it on her relationship with Seth Meanwhile, Donna LaDonna catches Maggie cheating on Walt and blackmails her into keeping Carrie away from Sebastian.

Carrie is thrilled when the junior-senior lock-in provides the perfect cover for a night out in Manhattan with Larissa and her Interview co-workers - until a surprising encounter turns her night upside down. Maggie and Mouse confront Sebastian about his feelings for Carrie and tell him he better make a grand gesture if he stands any chance of winning her back. Harlan finally convinces Tom to go on a double date, with surprising results. Meanwhile, Maggie tries to find the courage to tell Walt about Simon before Donna LaDonna does.

When Dorrit goes missing under Carrie's watch, Carrie lashes out at Sebastian, the one person who can help her find Dorrit. Mouse butts heads with West, a popular jock who, much to her chagrin, stole her spot as number one in the class. Walt surprises himself when he confides in someone completely unexpected. Meanwhile, Tom finds himself in uncharted territory when it comes to women and turns to Larissa for advice.

On her seventeenth birthday, Carrie torn between an opportunity to mingle with New York’s literati and spending time with her friends and Sebastian. Mouse goes to extensive lengths to impress a Harvard alum who has her eyes set on West, with hilarious results. Walt starts taking responsibility for his previous actions. Elsewhere, Dorrit’s search for the perfect gift for Carrie lands her in a sticky situation with romantic possibilities.