It's Halloween, and everyone in Charlie's small town is excited for this year's festivities. But for Charlie, Halloween's just one more reminder that his cousin Billy isn't around anymore. When Charlie runs into some neighbourhood bullies who are after his candy, he heads off into the woods to escape. He quickly gets lost, but spots a kid who he thinks is Billy. As Charlie chases after him deeper and deeper into the woods, he finds himself entering Monsterland - a mysterious place where werewolves live amongst trolls and goblins. Here he meets the Prime Minister, a vampire who tells Charlie he may be able to see his cousin again in this strange new land. Accompanied by a hulking monster chaperone, Charlie's determined to find out just what happened to his cousin, and sets off to explore the secrets hiding in this uncharted territory.