It's Always Sunny in Philadelphia - Season 8 - Eps 7: Frank's Back in Business
With Charlie under his wing, Frank cleans up so he can get his hands dirty and help out his old company with one last big merger. An unwritten rule of the bar gets the rest of the gang caught up in a case of mistaken identity.
About It's Always Sunny in Philadelphia

Title: It's Always Sunny in Philadelphia
First Air Date: 2005-08-04
Last Air Date: 2023-07-19
Status: Returning Series
Rating: 8.278/10 (from 1130 votes)
Language: EN
Seasons: 17
Total Episodes: 169
Network: FX FXX
Genres: Comedy
Production Companies: 3 Arts Entertainment, Bluebush Productions, FX Productions, RCG Productions
Synopsis
Four egocentric friends run a neighborhood Irish pub in Philadelphia and try to find their way through the adult world of work and relationships. Unfortunately, their warped views and precarious judgments often lead them to trouble, creating a myriad of uncomfortable situations that usually only get worse before they get better.
Cast

Charlie Day
Charlie Kelly

Glenn Howerton
Dennis Reynolds

Rob McElhenney
Ronald 'Mac' McDonald

Kaitlin Olson
Deandra 'Dee' Reynolds

Danny DeVito
Frank Reynolds