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.

On her seventeenth birthday, Carrie is 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.