Max feeds his pet mouse, Moose, a hunk of stinky cheese every morning, except this morning. Moose is missing Max is sure a monster has eaten his pet and vows to avenge him, by catching the monster and bringing him to justice. But how do you catch a monster you've never seen? Max uses clues the "monster" leaves behind as he builds trap after trap to catch this monster. In the end he discovers things are not quite what they seem.