Mary's sudden arrival has everyone in the family wondering what happened between her and Wilson. Only Mary knows and she's not telling. Her presence delights Annie, who goes out of her way to make her daughter comfortable, even offering her the converted garage apartment. But not everyone is happy to see her. Ruthie feels that Mary owes everyone an apology for the actions that led to her moving away.

Annie quits her job at the private school without discussing it with Eric first and he feels completely left out. Mary tries to call Wilson and learns from his landlord that he has moved out of his apartment. Simon uses Robbie's car to practice driving and gets him in trouble when Simon smashes into Matt's car. Robbie's brother Ronald stops by at the Camden home for a visit. Mary gets an unexpected visit from Ben, the fireman she kissed. Ruthie's old teacher Ms. Riddle starts working at Ruthie's school.

Matt and Sarah argue over their wedding plans and their agreement to forego buying an engagement ring and seek Eric for advice, who isn't happy with Matt for getting engaged in the first place. Because of Eric, Matt buys Sarah a fake engagement ring. Mary and Lucy fly to Buffalo for a weekend, or at least that's what Lucy thinks as Mary makes plans of her own. At the airport, Lucy meets a police officer who invites her and Mary to double-date with him and his brother.