It's Always Sunny in Philadelphia: Season 7, Episode 1

7 - 1: Frank's Pretty Woman

Frank wants to marry a prostitute and the gang can't talk him out of it. While Dee sets out to burnish the hooker's heart of gold, Charlie takes a different tack: He tries to set Frank up with another woman. Meanwhile, Mac has put on a lot of weight. "I'm cultivating mass," he tells Dennis.