The story opens in the Mushroom Kingdom with Mario and Luigi entering the Mushroom Castle basement, where Mario gets right to work, singing as he does so. Just then, gigantic pipes start popping up in the basement and in the courtyard. Various enemies from "Super Mario World" pop out of the pipes and attack the guards, but the Mario Bros. fight back. Bowser comes out of the largest of the pipes in his Koopa Clown Car and proposes marriage to Princess Toadstool. He then leaves her one week to decide on his proposal, but she rallies her troops and takes off after him.