Bowser begun to bring forth reinforcements,figuring a way to kill the Super Mario Bros. Not only Bowser brought Tatanga,but also Wario & Waluigi.
At the Mushroom Kingdom,Mario & Luigi begun fixing a leak at the Water Tower. While celebrating with Peach & Daisy,They heard a commotion going on in the city. Mario & Luigi confronted Bowser,But gets overpowered by Wario & Waluigi while Tatanga captures Peach & Daisy. Mario,Luigi,& Toad escapes with the help of Toadette,who reveals that she has been knowing about Mario & Luigi being heroes when they beat Bowser until she learns that Bowser is planning to call out reinforcements.
Mario & Luigi quickly infiltrates Tatanga's ship where He plans to marry Daisy. Mario & luigi fought against Wario & Waluigi and defeats them. Toad & Toadette quickly damaged Tatanga's ship,causing it to was knocked into a Pool of Lava. Mario & Luigi battles with Tatanga. They use each Super Leaf to turn into Raccoon Mario & Fox Luigi & defeats Tatanga by sending him airborne.
Toadette tells Mario & Luigi that Tatanga,Wario,& Waluigi are only the beginning. There will be more coming. Mario assures Toadette that he & Luigi will keep on fighting. Toad asked Toadette on a date,which she agrees.
Mid-Credits:
Toadsworth was informed that They found Bowser's file that contains a secret weapon. Meanwhile,A capsule slip out and inside of it was a small version of Bowser.
Post-Credits:
Wario & Waluigi are wonders around when a Skeleton Claw of Bowser emerges from the lava.