While both couples, Annie and Eric, Patricia and Morgan Hamilton, spend a romantic Valentine's Day camping, Matt is left in charge of the rest of the family and allows chaos to rein in the Camden household. His preoccupation with his date and Mary's party allows the dog, Happy. to slip out of the house in search of her puppies. When a car hits Happy, the family holds a vigil, aided by a caring veterinarian. Simon blames Matt for the accident. Lucy is enjoying her first Valentine's Day with her boyfriend Jimmy Moon.

Mary pays a rare visit to detention and meets Camille—a wild, free-spirited girl who loves to break all the rules. Against Mary's better judgment, the girls become friends, and Camille talks her into making a foolish decision. Back at home, Eric and Annie counsel a man who used to work with Eric and is harboring a painful secret. Lucy confuses her father with a desire to research other religions, while Simon and Ruthie run into trouble at the pet store.