The Legend of the Super Mario Brothers is set in a future where a massive superstructure that houses more people than ever before has been constructed. Mario and Luigi work as plumbers in the superstructure's enormous infrastructure. They must race to save the superstructure after the militant Bowser plans to overload the energy system through a construction project, which could destroy the structure and kill its inhabitants. Mario, Luigi, and their dinosaur friend Yoshi work to stop Bowser's plan, though it ultimately leads to Yoshi sacrificing himself so the brothers can flood the area and safely disperse the overloading energy, even if it means they and Bowser perish in the process.