Mac, Charlie and Dennis buy a boat to "throw some P. Diddy-style parties," as Mac puts it, and, Charlie insists, to harvest shrimp (or barnacles). They end up with a run-down houseboat, the Drowning Sailor, and Mac and Dennis order Dee (who didn't invest in it) to clean it up. Frank, sledgehammer in hand, offers to help.
There's a heat wave in Philly, so Mac and Charlie decide to fix up an abandoned pool after they're denied admittance to a swim club. Meanwhile, Dennis and Dee try to beat the heat in a more "dignified" manner.
After Mac's mother (Sandy Martin) burns her house down with a cigarette, Mac decides that she should move in with Charlie's mom (Lynne Marie Stewart). Meanwhile, Frank offers to take care of the ailing Dee because he wants her to take care of him when he's old.
Dee's pregnant, and she tells the guys that one of them made her that way during a Halloween party that none of them can remember. So they try to piece the evening together, "Potemkin"-style, aided by Artemis (Artemis Pebdani) and the McPoyle brothers (Nate Mooney and Jimmi Simpson).
Dee takes a job as a substitute teacher and decides to take her students on a field trip to Broadway. The principal (Dave Foley) won't allow that, so it's a screening of the gang's movie---"Lethal Weapon 5"---instead.
When the gang goes to Atlantic City for a charity benefit, Frank, Dee and Mac get lost en route. But Dennis and Charlie hitch a ride to town and have the time of their lives. Philadelphia Phillies Ryan Howard and Chase Utley have cameos.
In Part 1 of the two-part Season 6 finale, the gang sets out to discover the joy of Christmas. Their holiday adventure includes a sleighful of stolen toys, childhood videos, naked elves and a bloody encounter with Santa Claus.
In the conclusion of the Season 6 finale, the gang sets out to discover the joy of Christmas. Their holiday adventure includes a sleighful of stolen toys, childhood videos, naked elves and a bloody encounter with Santa Claus.