Barbara hooks up with Mac to make Frank jealous, which leads to retaliation from Dennis.

After Mac arrives to the bar with scratches on his neck and exhibiting strange behavior, Frank comes to the conclusion that he is the serial killer terrorizing young women in Philadelphia. Frank sets out with his trusty chainsaw and a doubtful Charlie to find evidence to implicate Mac in the murders. In search of another suspect, Dennis and Dee do a little role-playing in order to help themselves better understand who they might be dealing with.

When Dennis is mistaken for a recently released child molester, he is more bothered by the fact that the guy is overweight rather than him being a sex offender. Meanwhile, Mac tries once again to bond with his ex-con father, who shows an interest in Dee.

Part 2 of 2. Dennis, Frank, and Dee find unique ways of coping with the apparent loss of their friends.

The waitress is getting married, Dee is jealous that she's beating her to the altar, so she tries to derail the wedding.

Mac's mother is left homeless after she burns down her house, which leaves Charlie and Mac with no choice but to make new living arrangements; when Dee feels under the weather, Frank tries to muster his paternal instincts to care for her.

After years of being mistreated by Frank during the holiday season, Dennis and Dee decide to teach him a lesson. Meanwhile, Mac and Charlie reflect on their childhood Christmases, and realize that they were not as joyous and wonderful as they remembered.

Mac, Charlie and Dee struggle with their faith as Charlie's mom fights cancer. Meanwhile, Frank loses his memory amidst a search for buried treasure.