After saving the Mushroom Kingdom from Bowser and the rest of the Koopas in Super Mario 3, Mario and Luigi needed to recuperate from their adventures. Together they agreed that the best place to vacation was a magical place called Dinosaur Land.
But while Mario and Luigi reclined on the beach for a relaxing nap, Princess Toadstool disappeared, apparently seized by evil forces. After searching for hours for their missing friend, Mario and Luigi came upon an enormous egg in the forest. Suddenly the egg hatched, and out popped a young dinosaur
named YOSHI, who proceeded to tell Mario and Luigi a sad tale of how his dinosaur pals were sealed in similar eggs by a group of monstrous turtles.
"Monstrous turtles!," exclaimed Luigi. "Bowser and his bunch have returned!". Mario slowly nodded his head in agreement and,
along with Luigi and Yoshi, set off across Dinosaur Land to find the Princess and to free Yoshi's friends.