Ghosthunters and the Muddy Monsters of Doom! - 4

To earn his Ghost hunting diploma-Tom's got to nab a deadly twelfth messenger. But while on the hunt in the haunted town of Bogpool-Tom stumbles into the mucked-up lair of a mud-loving Minotaur who has an entire army of ghosts at his command. Suddenly-there's a lot more at stake than Tom's graduation. This raging beast is dead-set on doomsday and that's no bull!