Every year the town of Decalburg throws a big bash called the Sticker Fest. On this joyous day the Sticker Comet pays a visit, and according to legend brings with it the power to grant wishes courtesy of the Divine Sticker Beings. Clearly, this is a party nobody should miss.
It seems Bowser got the memo. He shows up just in time to crash the party and touch the Sticker Comet, causing a big explosion and scattering pieces of the comet and the Royal Stickers across the land. When the dust settles, Bowser has managed to grant himself some shiny new powers, and he proceeds to terrorize everyone in sight!
Joining forces with Kersti, ambassador to the Royal Stickers, Mario must track down the missing royalty and comet pieces, to restore the comet and once again bring order back to the land. He may have to give Bowser yet another smackdown along the way!
Source: Official Site
