The game follows the traditional storyline of Princess Peach getting kidnapped by Bowser and his children, the Koopalings and Bowser Jr. When Mario, Luigi, Blue Toad, and Yellow Toad are celebrating Princess Peach's birthday in her castle, a large cake appears. Bowser Jr. and the Koopalings emerge from the cake and trap Peach inside. The cake is loaded onto Bowser's airship and it takes off, with Mario, Luigi, and the two Toads giving chase. The Toads in the castle then grant them access to the new items, the Propeller Mushrooms and Penguin Suits.