Curse of Arachnaman follows the events in the first three books in the Masks series. Eric is settling down into a near-normal existence. He's learning to cope with a different kind of closet — being kept from talking freely about his relationship with Calais and the other superheroes — as well as an increasingly protective mother, his sister's new squeaky-clean boyfriend, and a bingo-obsessed best friend.

Eric also learns that, sometimes, being an asset to the forces of good means simply being himself. In the meantime, Vintage City is under siege from a new threat, one which is proving to be much more dangerous than all of the other supervillains the heroes have faced combined. Good people find themselves at the mercy of an angry lunatic who will stop at nothing to purge the city of what he sees to be undesirable elements.