A man was reincarnated as Van, a boy of noble birth, who grew up to become a child prodigy through hard work. But when it was discovered that he possessed "production magic," he was immediately relegated to a remote village. However, his magic, which was called useless, turned out to be truly extraordinary, capable of producing anything as long as he had the right ingredients! With the knowledge from his previous life and the overpowered magic, the small, poor village will grow to become into a great city.

An angel made a mistake, resulting in Shiihara Daiki’s death. In order to hide the mistake, he was then sent to a different world. The angel will grant him one wish as a payment for keeping it a secret. Daiki asked for a Heavenly Castle floating in the sky without hesitation.

Suddenly a floating castle appeared in the new world, which causes confusion amongst the people. They attempt to contact Daiki in various ways. A country tries to steal it by force, while another seeks to befriend him. What in the world will Daiki do?