Responsibilities fly out the window when Eric and Annie enjoy seperate nights out on Friday. Although the reverend can't find anyone to hang out with him, so he calls a bewildered Matt. Annie is conferring with a professor (guest-star Jeff Yagher). Mary strays even further away from her parent's image of her when she is tempted to drink and smoke one night after work. Also, Mary makes friends with married co-workers Frankie and Johnny (guest-stars Chyler Leigh, Nathan West) with questionable morals while working the late shift. Matt blows Simon's chance at a big date with an older woman (guest-star Katie Stuart) when Matt is distracted by a close encounter of the female kind and forgets to pick up Simon. Also, Lucy gets a taste of the not-so-glamorous side of parenting when her and a classmate take care of an egg.

Exasperation reaches an all-time high in the Camden household, as Eric and Annie helplessly watch their oldest daughter Mary and her worrisome friends continue to head down the path of destruction and into the hands of the law. When Frankie (guest-star Chyler Leigh) expresses interest in signing up for college classes Mary starts checking out Lucy's early application packets. Meanwhile, Simon has a hot date and Lucy gets a weird proposition from a classmate. Lastly, Ruthie discovers manipulative fun of keeping a diary--- much to the embarrassment of Eric and Annie when she sees them having SEX!

Tensions run high as a doubtful Julie lets Mary baby-sit Erica, only if Mary has no visitors. But when Frankie (guest-star Chyler Leigh) comes by and begs Mary to take care of her baby Mercy, Mary can't resist helping her. Then, Mary is then caught with an open bottle of beer while babysitting. Meanwhile, Lucy volunteers to chaperone Ruthie's sleep over and to watch the twins. Also, Simon is on a quest to change his image and does this by piercing his ear. Matt pursues a woman who wants nothing to do with him. Also, Eric and Annie clash with Mary's disreputable friends.

As Annie plans a mysterious day of cleaning as Eric discovers the shocking news that Mary ran away from ""The Colonel""'s to come back home because of a devious scheme she had with Robbie and freaks out. Eric is convinced that more trouble is brewing and goes to insane lengths to find answers. In reality, Mary is heading home for a huge surprise birthday party for Eric, attended by all the people whose lives he's changed for the better in the past few years. Chores at home are interrupted, however, when Ruthie discovers Frankie and Johnny's baby, Mercy at the Camden front doorstep. Meanwhile, Lucy stays with her friend Mike's (guest-star Jeremy Lelliot) near catatonic mother for the day, and drops a proverbial bomb on Lucy. Also, Matt and Simon try to figure out why they delivered Mrs. Bink (guest-star Eileen Brennan) to the hospital.