Billy is a monster hunter. That's because his home is infested with all kinds of monsters! One week, Billy does battle with the monsters in his bedroom, in the bathroom, even in the kitchen. But the problem is that monster hunting is a messy operation, and Billy's mom isn't so thrilled about all the messes she finds - water covering the floor, clothes thrown on the furniture, or food strewn about in the kitchen. So, when the hunting goes too far for Mom, Billy learns that monster hunting can and must be done with the proper tools, such as a vacuum and sponge.