Cursed as a child to never have an heir, Prince Oscar seeks the continent's most powerful witch, Tinasha, hoping she'll break his curse. To meet her, he'll have to climb her formidable tower, which grants a wish to whoever reaches the top.

Fourteen-year-old Suzuki Iruma has just been abandoned and sold to a demon by his irresponsible parents! Surprisingly, the next thing he knows he's living with the demon who has adopted him as his new grandson, and has been transferred into a school in the demon world where his new "demon" grandfather works as the principal. Thus begins the cowardly Iruma-kun's extraordinary school life among the otherworldly as he faces his true self, takes on challenges, and rises to become someone great.