"Monkey-opia is going to be brilliant!" When Monkey is sent into space by a team of scientists, he expects smooth sailing. But not all goes according to plan, and Monkey's spaceship crash-lands in a nearby forest. Convinced he has discovered a new planet the power-mad Monkey claims the peaceful Woods as his own Monkey-opia! He declares that all other animals must be banished, and he uses bizarre inventions, such as the Cluck-Cluck Zeppelin and Metal...

An average-looking guy with a not-so-average problem: trying to find an opponent strong enough to take on, Saitama is trapped in the Monster Association's underground labyrinth while Superalloy confronts Garo and experiences fear of his opponent's strength.