The second season of It's Always Sunny in Philadelphia, premiered on FX on June 29, 2006. The season contains 10 episodes and concluded airing on August 17, 2006.
An accident that puts Charlie in a wheelchair opens up a window of possibilities for the gang. Meanwhile, Dennis and Dee’s estranged father reenters their life in hopes of starting anew with his children and soon discovers that he enjoys the lifestyle of their friends.
When the gang learns that they are in danger of losing their bar due to a zoning mishap, they resort to some outlandish and extreme methods to prevent that from happening. Meanwhile, Frank isn’t too happy when his wife returns to town.
After quitting their job due to Frank's continuing interference, Dennis and Dee decide to seek alternative income by going on welfare. Meanwhile, Mac and Charlie must now bear the consequences of their friends’ departures from the business.
Barbara hooks up with Mac to make Frank jealous, which leads to retaliation from Dennis.
Frank runs into an old adversary at the gym when he begins teaching Dee to box after she was robbed. Hoping to make some extra money on the side, Mac and Dennis make preparations for Charlie to compete in an underground street fighting match.
After being arrested for arson the gang is sentenced to do community service. Frank makes an effort to connect more with Dennis. Meanwhile, Charlie is also ordered to attend AA where he makes a startling discovery that might be beneficial in his ongoing quest to hook up with the Waitress.
Mac and Dee become uncomfortable when the rest of the guys decide to make some extra money by exploiting the similarities between a water stain and the Virgin Mary. A reunion with someone from the past, stirs up forbidden feelings within Dee.
Driven by Frank's insight into the world of politics, Dennis pursues a political career by running for office.
Dennis and Mac make a decision to take away all rules concerning moral and behavioral etiquette at Paddy's after an argument about the Constitution. Frank uses the decision and it's following consequences to his own gain. Meanwhile, Charlie tries to convey his love for America by protesting while Dee attempts to reaffirm her goal of being an actress.
Dee receives e-mails from a stranger claiming to be her and Dennis' real father. Meanwhile, Mac decides to visit his father who is in prison.