 It suddenly hatches and out of it comes a young dinosaur named Yoshi, who tells them that his dinosaur friends have also been imprisoned in eggs by evil Koopalings.Mario and Luigi soon realise that it must be the evil King Bowser Koopa and his Koopalings.Mario, Luigi and Yoshi set out to save Toadstool and Yoshi's dinosaur friends, traversing through Dinosaur Land for Bowser and his Koopalings.