Brendan's ego gets out-of-hand that the gang decides to hold a douchebag intervention. Meanwhile, PJ's college friend Lyssa and her all-things-New-York entourage descend upon Chicago while Andy suffers from an overly friendly neighbor.
P.J. has to deal with both her relationship with Jack and Bobby's doubts concerning marriage. The boys have a mustache-growing contest, and Meredith gives birth.
P.J. tries to keep her new relationship from the guys, Brendan works over plans for his new club, and Mike decides to keep his mustache long after the contest is over.
The gang's annual board game decathlon at Crowley's causes conflict between P.J. and Bobby. Stephanie studies the habits of the guys for a research project.
When Aunt Phyllis (PJ's idol) comes to town, PJ's enthusiasm cools when the woman begins dating one of her guys. Bobby is far less enthusiastic about meeting one of Mike's baseball idols, a very self-centered has-been.