The Hand of Midas is the first episode of Regular Show's fifth season. It follows around Mordecai, Rigby and Wally teaming up with Aladdin, Cassim and Genie to find the legendary Hand of Midas.
Mordecai, Rigby and Wally are listening to Welcome to the Forty Thieves on Wally's boombox. As Wally gets reminded about his grandfather's visit to the park, Mordecai and Rigby read one of Wally's books his grandfather gave to him, about a treasure called "The Hand of Midas". Outside, while playing baseball using vaccums for bats and basketballs for baseballs, Mordecai, Rigby and Wally get knocked out. When they awaken, they find themselves in the lair of the Forty Thieves with Aladdin, Iago, Abu and Carpet.
Mordecai finds himself dressed in another version of Cassim's robe (painted red), Rigby as palace guard and Wally as a woodcarver. They meet Aladdin, Iago, Abu and Carpet, who are shocked to discover that his father is not their prisoner at all, but their leader: Cassim, the King of Thieves, the very man he fought during his wedding's invasion. But, family or not, Aladdin, Mordecai, Rigby, and Wally have trespassed in their lair and the Forty Thieves are eager to have them punished for it. Cassim, however, suggest that Mordecai instead face "the Challenge" - an initiation ritual - where he must defeat another one of the Forty Thieves and take his place. Mordecai eventually defeats Cassim's right-hand man, Sa'Luk, in battle, gaining him a place among the thieves. It is then that he learns the true motives behind the raid, and his father's leave of absence from his family: he had discovered evidence of the existence of the Hand of Midas, a powerful artifact that can transform anything it touches into solid gold. Cassim believed that, with the Hand, he could return to his family and give them the life they deserved instead of one living out in the streets, and had instigated the raid so he could capture the oracle's staff so he may question the seer as to the precise whereabouts of the artifact.
Aladdin convinces Cassim, Mordecai, Rigby and Wally to come back with him to the Palace as his guest and, for a while, he is happy to spend quality time with his son. But the pull of his obsession with the Hand is too great, and Wally ends up stealing the Oracle's staff and getting captured by the guards of the palace. Aladdin, Mordecai, Cassim, and Rigby help their friend escape, but is recognized by the Captain of the Guard, forcing them to flee the city with Cassim and Iago, Aladdin's treasure-loving parrot. Rather than abandon Jasmine (like his father had left him), Mordecai angrily confronts Cassim and returns to Agrabah to take responsibility for his actions. Meanwhile, Iago and Cassim return to the thieves' cave to find that Sa'Luk is still alive and is now the leader of the remaining thieves. Sa'Luk convinces the remaining thieves that Cassim sold them out to the palace guards and was to blame for the recent raid upon their hidden fortress (in actuality it was Sa'Luk who told the guards so he could frame Cassim). Cassim, desperate to prove his loyalty, is forced to use the stolen oracle in order to find the location of the Hand, and then lead his men there. The Oracle directs them to The Vanishing Isle, a great marble fortress built on the back of a gigantic undersea turtle that periodically dives to the bottom of the ocean, taking the golden Hand with it.
Iago manages to escape from the group, and goes off to lead Aladdin, Mordecai, Rigby, Wally and Jasmine to his imprisoned father. Aladdin and Cassim reconcile, and Mordecai and Rigby retrieve the Hand just as the turtle is beginning to submerge when they are attacked by Sa'Luk. Then, after struggling to escape the flooding fortress, Wally throws the Hand of Midas to Sa'Luk, who doesn't know the legend of the Hand. Foolishly grabbing it by the gold hand (instead of the wood handle), Sa'Luk is turned into gold. Aladdin, Mordecai, Rigby, Wally and Cassim manage to escape with the Hand but, finally realizing how much pain his obsession with the trinket had caused, Cassim decides to toss it into the sea. But Wally catches it, deciding to give it to his grandfather. As the movie closes, Aladdin and Jasmine finally tie the knot, and Cassim accepts the parrot Iago as a traveling companion as he goes off once again to see the world, while Mordecai, Rigby, Wally, and the Hand of Midas return to the park.
A reprise of Arabian Nights is then sung; the Peddler makes an appearance at the end of this film to mark the end of the legend of Aladdin