Billy Hooten, Owlboy Books in Order

Comic-loving Billy Hooten follows a cry for help into a cemetery and discovers Monstros City beneath his hometown. Becoming its superhero Owlboy requires protecting bizarre residents and mastering strange gadgets while still navigating ordinary school life and bullies.

Billy accidentally leaves the passage to Monstros City open, allowing his troublesome neighbor Victoria to follow him. The city's magic amplifies her destructive tendencies into a dangerous power, leaving Owlboy responsible for protecting the place he has inadvertently endangered.

Superhero Billy Hooten discovers that his previous enemies have all been working for the Monarch. Learning the mastermind's unexpected identity complicates Owlboy's attempt to defend Monstros City against a powerful opponent with a deeply personal reason to hate him.

While Billy deals with a visit from his elderly great-aunt, a villain unleashes the enormous Zis-Boom-Bah on Monstros City. Owlboy needs an alternative to a military weapon that would destroy the monster and much of the city together.