Okarun, a high school boy obsessed with supernatural phenomena, is cursed by Turbo Granny! Along with his classmate Momo Ayase, he challenges Turbo Granny to a game of tag as a means to lift the curse. If the two can stay out of her reach until the finish line, they'll win. But Turbo Granny's assassin, a bound spirit in the form of a giant crab, has other plans!