Fitness is crucial in life, and often times has a link with one's ability to defend themselves in problem situations. One thing that exemplifies this idea is an episode of a popular TV show called It's Always Sunny in Philadelphia. The series centers around five bar owners in Philadelphia named Frank, Dennis, Mac, Dee and Charlie. Frank is a father to Dennis and Dee and the others are just good friends. In an episode of the show entitled Hundred Dollar Baby, a play on Million Dollar Baby, Frank makes an attempt to teach his daughter Dee self defense after an incident in which the other three men left her to get mugged by a junkie. Frank uses a life fitness elliptical machine, life fitness equipment and dumbbells to get Dee into top physical form and able to defend herself.

Dee is left to fend for herself when her brother Dennis and friends Mac and Charlie ditch her and run away when confronted with a mugger. This turns into former boxer Frank, played by Danny Devito, instructing Dee to defend herself. While at the gym getting in shape, Frank runs into an old rival boxer and the two old foes throw jabs at each other for a while before it is decided that their two daughters will fight each other to finally settle the score. In order to get prepared for her fight against a clearly more experienced fighter, and to make up for Frank's horrendous coaching, Dee decides to start taking steroids. Hilarity ensues when the typical steroid side effects become a problem and Dee is left having to shave her face and deal with extreme fits of rage.

Meanwhile, after an argument with Frank, Dennis and Mac decide that they should put Charlie into an underground, unsanctioned and illegal street fighting tournament because they say he is the toughest guy they are friends with. Ultimately this is just a scam on their part to make money because they plan on betting on Charlie to win the fights they enter him in. In order to get him ready for his fights the three of them get really drunk and Dennis and Mac smash things on Charlie's back, such as chairs. To further prepare for his underground fights Charlie decides that he's going to start using Dee's steroids and towards the end of the episode also deals with fluctuating moods, alternating between crying, being angry and hysterical laughter.

To end the episode, Dee finds out that Charlie has been taking her pills and the two of them get in a fight which leaves them both in jail. Mac takes Charlie's place in the underground fighting competition at Dennis's suggestion and is brutally beaten. On the way back to their bar the friends meet the same mugger as before and it comes out that Dennis switched his bet when Mac fought and bet on the other guy, resulting in him winning lots of money. Mac then eggs on the mugger to rob Dennis and that plot line comes to a conclusion.

In the other plot line of the episode Frank decides that since his daughter is in jail he will step up and fight his former nemesis in the ring like he always wanted to. Frank uses trickery and punches the other man before the bell, resulting in him falling and knocking his daughter down, who then hits her neck on the side of a stool like in Million Dollar Baby. The episode reaches it's end with Frank walking away nervously and the credits rolling.