A young girl, a big fan of Mario and his games and a skilled inventor, is working in the basement of her home with her AI assistant, Beep-O, to finish off her latest creation called the SupaMerge helmet – a device that can merge any two objects it targets into a single entity, in the hopes it could solve an energy crisis. However, the helmet has an overheating problem when merging a flower with a lamp. After leaving to take a lunch break, her basement is suddenly invaded by a group of Rabbids via their Time Washing Machine, who start to explore and cause chaos with her stuff. One of the Rabbids soon takes a keen interest in the SupaMerge helmet and puts it on, before messing around with it, merging one Rabbid with a wig and the girl’s phone and changing him into Princess Peach Rabbid, another with a red object into Mario Rabbid, and another with a toy sunflower and some glasses into a living Sunflower. But in having fun with the helmet, the Rabbid strikes the Time Washing Machine, sucking all of the Rabbids, Beep-O, and the girl’s stuff, into a dimensional vortex.
In the Mushroom Kingdom, Mario, Luigi, Princess Peach, and Yoshi, attend a ceremony for the unveiling of a new statue to Peach at her castle, when they suddenly spot a giant vortex forming above Peach’s castle, which sucks up everyone attending the ceremony and deposits them elsewhere. At the same time, the Rabbids arrive in the Mushroom Kingdom, along with the girl’s stuff which is now gigantic in size. As they are being dropped across the Kingdom, Beep-O watches as the SupaMerge helmet is merged to the Rabbid wearing it, who in turn merges more Rabbid with other objects before disappearing elsewhere. As the Time Washing Machine, now gigantic, is about to smash into Beep-O, it is soon rescued by Mario, who teams up with Princess Peach Rabbid and Luigi Rabbid in order to tracked down the SupaMerge helmet. Aided by a mysterious figure that sends Beep-O e-mails, the team are given special weapons to combat the Rabbids that oppose them, rescuing Luigi in the process from a Rabbid merge with a Piranha Plant, and eventually track down the helmet to a giant tower of building blocks. However, Bowser Jr. quickly grabs the Rabbid merged to the helmet and calls it “Spawny”, before leaving the group to deal with a Rabbid resembling Donkey Kong.
Realizing they need Spawny to undo the damage to the Mushroom Kingdom, the group soon head off to find the pair, acquiring aid from Princess Peach, Rabbid Mario, Rabbid Yoshi, and Yoshi, while contending with further tricks by Bowser Jr.. As they continue to deal with more attacks by merged Rabbids, Beep-O begins to notice that the vortex from earlier is still in the sky and growing in size, eventually discovering that a corruptive entity known as the MegaBug, is causing it and gaining strength from every Rabbid that is defeated and sent back to Peach’s castle completely returned to normal. After battling against Bowser Jr. once more, the group manage to rescue Spawny, only for him to run away and be captured by the MegaBug and merged into it. Shortly after witnessing this, Bowser Jr. discovers that his father Bowser is coming home early from a vacation, and rushes to warn him of the danger to their castle from the MegaBug. Mario and the group soon arrive, and witness the MegaBug merge with Bowser into the powerful MegaDragonBowser, forcing the group to fight and defeat him, freeing Bowser and Spawny from its clutches. A relieved Bowser Jr. soon apologies to the group, thankful his father was saved.
Sometime later, the group return to Peach’s castle for a new unveiling ceremony with the Toads and the Rabbids, in which a statue of Rabbid Princess Peach is unveiled to the crowd. Delighted, Rabbid Princess Peach decides to take a photo of herself and the rest of the group. In an epilogue, Beep-O spots the Time Washing Machine, and decides to send letters back to the past, in order to warn themselves of the dangers they’ll, but later consider it might not be wise, and questions what could possibly go wrong from such actions.
Fan Review : 63% Good
Excellent: 13% | Average: 25% | Poor: 0%