As a lionhearted boy who can't wield magic strives for the title of Wizard King, four banished Wizard Kings of yore return to crush the Clover Kingdom.

When a lazy, erotic-game loving Otaku is transformed into a girl by his younger scientist sister's experiments, he becomes determined to change back, only to recognize that with his new opportunity, he may want to turn his life around.

Rud, an adventurer with the highest defence ever recorded, serves as a tank while exploring dangerous labyrinths in search of a treasure capable of curing his ailing sister. After being unjustly expelled from the Hero’s Party, he discovers the true nature of his hidden abilities and begins forging a new path alongside the companions who recognise his strength and selfless determination.