Simon rightly fears he'll catch roommate Ruthie's chicken-pox, but his enterprising hygienic measures fail to prevent contagion from her, or from Happy's fleas. When a robber carjacks them, Annie seems calm and hands their valuables, so Matt feels 'unmanly' and guilty. However, Anne breaks down at an identification lineup. Jimmy Moon stands against Lucy in the school elections, then turns to her parents for help. The church organist veers bizarrely from brilliance to disharmony.

Simon is surprisingly successful with Eric's suggestion to show how mind-games can convince people of crazy ideas by pretending he's shrinking; when he's overheard, Matt turns the tables, only to be beaten in the end. Lucy invites her classmate Shelby to dinner, curious about rumors that she suffers from bulimia; Eric lets Mrs. Bing drag him into meddling in her friend Mrs. Hinkle's situation.

With the twins birth impending, Eric makes the kids' life miserable by fussing and over-planning, yet blames Matt for preparing the youngsters for what's ahead. Annie adds to the mess by inviting over the Hamiltons, just so Patricia can help her ward off the parish busybodies, who forced a baby-shower on her so they can snoop around the church-owned home. Ruthie acts as if a victim when classmate Bobby points out her underwear visible by failing to wear school-regulation shorts. Her elder siblings are pushed to confront Boby's family, but his brothers aren't only taller, like their dog, they also bond with Matt and Mary and end up turning on the brats together.

Simon risks losing his paper-route unless he manages to collect the money from scrooge Malone and Mrs. Hinckle suggests how to trap him. Matt's married college president Jack Brenner's reputation is tarnished by at times even violent public controversy over a formally allowed affair with a grad student. Matt's friends and parents get involved including him. Mary bumped into Miles Olsen's car in the school parking lot, but he gets a date with Lucy.