Super Mario Bros. is the first ever platform adventure for the Mario Brothers. It shifted the gameplay away from its single-screen arcade predecessor, Mario Bros., and instead featured side-scrolling platformer levels. While not the first game of the Mario franchise, Super Mario Bros. is the most iconic, and introduced various series staples, from power-ups, to classic enemies like Little Goombas, to the basic premise of rescuing Princess Toadstool from King Koopa.
One day, the Mushroom Kingdom was invaded by the Koopa, a tribe of turtles capable of using powerful dark magic. Their magic was used to transform all the Mushroom People into inanimate objects such as rocks, bricks, and even horsehair plants, thus spelling the kingdom's downfall. Only Princess Toadstool can undo the spell and restore her people back to life, but she is being held captive by King Koopa himself. Mario hears of the princess's plight, and sets out on a quest through 32 stages to topple the Turtle Tribe and save the once-peaceful kingdom.