The Princess has been kidnapped by the evil Bowser, and it is up to Mario and brother Luigi to save the day.
The first ever platform adventure for the Mario Brothers has the player exploring level after level, with Bowser to contend with as the end of level boss. Power-ups include the Super Mushroom, which increases Mario's size and power, the fire flower, allowing him to shoot fireballs at enemies, and the ever important starman for a short burst of invincibility.
Mario is having a vacation in Dinosaur Land when he learns that Princess Peach Toadstool has been kidnapped by the evil King Koopa Bowser. When Mario starts searching for her he finds a giant egg with a dinosaur named Yoshi hatching out of it. Yoshi tells Mario that his fellow dinosaurs have been imprisoned in eggs by Bowser's underlings. The intrepid plumber has to travel to their castles, rescue the dinosaurs, and eventually face King Koopa himself, forcing him to release the princess.