When their grandfather falls into a coma, Dee and Dennis are notified that have been given legal responsibility on whether or not to pull the plug.
While they wrestle with the decision, Frank's obsession that Pop-Pop is hiding Nazi treasure sends Charlie and Mac off to track down a painting Charlie kept of his years earlier.
With the garbage men of Philadelphia on strike, Frank concocts a plan to undercut the union and get the contract to collect the city's trash. But when The Gang's elaborate plan starts to fall apart, everyone will get their hands a little dirtier than expected.
Dennis and the gang crash Maureen's wedding to make certain he'll be able to sever all ties, only to discover a union much scarier than kissing cousins.
Charlie and Dee become romantically involved with two members of a wealthy family, which arouses jealousy in Mac, Dennis and Frank.
The gang visit a therapist, who finds Dennis' psychology to be abnormal.
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.
Frank helps his old company complete a merger. Meanwhile, the gang gets caught up in a case of mistaken identity.
After slipping into an unhealthy obsession with computer games, The Gang wrestles to define the difference between the real and the virtual worlds.
The gang go out to celebrate at an upscale restaurant.
Frank and Dennis hold court at Paddy's Pub.