Mario, alongside a Rabbid (one of the characters from the Raving Rabbids series) doppelganger wearing Mario's hat, embark on a mission to free the Rabbids from Wario, who has taken over.
Mario invites 120 different residents of the Mushroom Kingdom to compete against each other in a gauntlet, with a mystery box as the prize for the winner.
Pauline is kidnapped by Donkey Kong while out on a shopping spree with Peach. Peach then finds Mario and tells him to rescue her otherwise he won't be having dinner.
SMG4 and Mario face off once again for War of the Fat Italians (WOTFI), but this time, there is more than their reputation on the line. Their channels are at stake as well.
Mario has to pay off his debt to the devil after losing at the casino. As a result, Mario is brought into the monster-filled world of Inkwell Isle, where he meets Cuphead and Mugman, who are more or less in the same boat as Mario.
Mario, SMG4, and Toad are back again for a trip. This time they go by train to visit Uniderpal Studios. However, there is a certain maniac with an overly inflated ego named Bob who wants to join them.