After Kerry and her boyfriend break up, Paul tries to cheer her up by getting Bridget to take her little sister with her to a party. Meanwhile, Paul and Cate try to discover what is hidden in Rory's secret box.

Having learned that her sister Maggie is having marital problems, Cate is nevertheless not too thrilled when Paul invites Maggie to stay at the house. Meanwhile, Paul and Cate are impressed with how mature Bridget has become after they agreed to let her go out with neighbor Donny Doyle, who is home from the Naval Academy. Bridget and Kerry wonder if Kyle has ulterior motives when he befriends Rory.

The rivalry between Cate and Maggie comes to a boiling point when Maggie gets a sexy, new makeover and gives Bridget a water bra as a gift. Tensions between the Hennessy sisters mount when Kerry and Kyle begin dating, while Bridget's popularity takes a nosedive after she dissed her friends for Donny. Paul becomes concerned when he finds an empty pregnancy test kit.

Cate is unprepared for the diverse reactions exhibited by Bridget and Kerry on their first day back to school since their father's death. Meanwhile, Jim tries his best to be helpful by making some questionable home improvements to the Hennessy home.