You will start off in Mario's house when Luigi tells you how peaceful (and boring) it is...or not! When you go out, Toad will come and scream that Princess Peach got kidnapped! Only one person could have done this......Bowser! So off to Bowser's castle it is!
When you arrive inside Bowser's castle (Someone left the front gates open) Bowser will say he was only going to launch his attack. Then, Peach appears in a cage. Then someone else shows up. He says he is called Count Bleck. He was the one who kidnapped Peach! After talking, he creates a vortex that sucks everyone in. (Even Bowser, despite how heavy he is! Yourself not included)
Then a pixl called Tippi awakes you and explains who they are. You are now going to travel to the town of Flipside. Meanwhile, Count Bleck and Natasia make Peach and Bowser marry each other.