Regular Show: Muscle Man, Big Winner

When Mordecai and Rigby fail at another task, Benson has Muscle Man and High Five Ghost supervise them. Mordecai and Rigby have to put up with Muscle Man and High Five Ghost's annoying shenanigans (including Muscle Man's "My mom!" jokes).

Muscle Man breaks up with his girlfriend, Starla, leaving him an emotional mess and unable to work. When Mordecai and Rigby are forced to pick up Muscle Man's jobs around the park, they attempt to reunite Muscle Man and Starla, until she begins to fall for Mordecai.

When Muscle Man and High Five Ghost are watching viral internet videos, Mordecai and Rigby say they can make a better video, and bet Muscle Man and High-Five Ghost $10. Muscle Man and High-Five Ghost make three videos that each get 900,000 views, and Mordecai and Rigby call it double or nothing.

Muscle Man invites his coworkers to celebrate the five years he has been at the park by going to "Fry-It-Up" (a local restaurant), but they are unable to attend due to previous engagements. (Mordecai and Rigby have dates with Margaret and Eileen, Skips, Pops, and Benson have to go lawn bowling, and High-Five Ghost has to go to his brother, Low-five Ghost's police academy graduation).

After their lunch break, Mordecai is ready to get back to work, but Rigby wishes to continue slacking off. Mordecai tries to convince him to get back to work, which makes Rigby begin to talk about how he can slack off at any time without Benson firing him.

When Muscle Man's father, Muscle Dad, dies, Benson asks Mordecai and Rigby to go along with Muscle Man to spread the ashes of his father's hat (which reads "World's Greatest Trucker") at the highest point at the Trucker Hall of Fame. While at a truck stop, three truckers tell Mordecai and Rigby that Muscle Man's dad wasn't really a trucker like he told Muscle Man when he was a kid but instead he was a forklift driver.

Sick of getting pranked by Muscle Man, Mordecai and Rigby decide to get even by giving him a fake lottery ticket for his birthday. Muscle Man scratches it and sees that he won one million dollars. Mordecai and Rigby planned on telling Muscle Man that it was a prank until Skips tells them that the last person who pranked Muscle Man with money ended up getting "pranked" back.

Muscle Man is walking with his girlfriend Starla and she tells him to go to a fancy dinner with her parents so they can take their relationship to the next level. But Muscle Man has a hard time being fancy so he asks Mordecai and Rigby to help give him advice.

Muscle Man wants to hide his bald spot at all costs.

Mordecai and Rigby want to stop Muscle Man from messing with Thomas.