From the web site of the publisher: "Many mouses are free in the farm. But we are gluck to have some cats to hunt the mouses. Unofrtunately the cats are not the best ones, and they are a little lazy also. If they are not in the right place, they will stay in his barrel and you catch no mouse." The kids throw a colored dice to move the barrel with the cat around the board as the mouses. Only when the barrel is within a magnetic range from a certain number of mouses, the cat spring out of the barrel and the mouses can be collected.