From the back of the book:
A multi-player adventure game for you to run. If you can. If you dare.
Monster Horrorshow is a magical world of nightmare and adventure where you and your friends fight for survival. Here you can live (and die) for days, weeks, months, even years - because, unlike any other adventure gamebook, Monster Horrorshow takes place in your head.
First you have to learn how to become a Werewizard, someone who will run the whole show. The ultimate referee whose word is law. To qualify you have to pass through the dreaded Labyrinth of Squat, a short solo adventure. Then the Horrorshow begins.
Everything you need to run the Horrorshow is here including a complete game system, monster cards and a ready-to-play horror adventure scenario. But remember, this is only the beginning, the real game depends on your imagination...