Bowser has returned to the Mushroom Kingdom and takes away Princess Peach again to the birth of his new galaxy. The Mario Bros try to stop him and rescue Peach but are wiped out and sent flying off the face of the planet. They are recovered by the mysterious princess of the stars, Rosalina who helps them on their path to Bowser's Galaxy by collecting the power stars from all over the universe. Meanwhile, new characters such as Yoshi join the adventure and Princess Peach discovers her true origins.
