After explosions on the moon cause the earth's tides to wipe out most of humanity and civilization, monsters of legend rise to take their place. BROKEN MOON opens in a massive city of vampires who have taken to polluting the skies to block out the danger of the sun. A human spy, Avery, escapes the city with valuable information about the vampires' plans and reconvenes with her small tribe-few of whom escape with their lives following a confrontation between the vampires and a pack of werewolves.
The werewolves, led by the strangely peaceful Rantz, forge a reluctant alliance with Avery and her companion David when they learn of the Nosferatu's plot to poison the oceans and render the earth inhabitable. But their numbers are small, and the werewolf-human army will require a much larger contingent to take on the vampires. Going on a hunch and a myth, Rantz leads the small group to the City of Frankenstein, where the "good doctor" has continued his experiments well beyond the original monster and created a veritable village of Frankenstein monsters. But what will sway him to their side?