The Gang's in Dublin! Dennis longs for a charming, authentic European experience, but ends up helping Frank with some of his business's "dirty work." Mac and Charlie learn about their Irish heritage. Dee rushes to the set of an Irish soap opera, where she will play the role of "Obnoxious American MILF." 

Guided by a young priest, Mac spends a day at the seminary to truly understand what it takes to become a priest. Dennis and Frank plan an elaborate trap at the castle to humiliate Charlie's pen pal. Dee prepares for a date with an Irish doctor, only to find herself sinking in a bog. Having learned of his pen pal's true identity, Charlie bonds with him and makes a choice that will forever change the Gang.