This very cute comedy series is about the adventures of a very kind and précis cat, Leopold, and two mischievous naughty mice. It is about how Leopold the cat, deciding to play a trick on the "hooligan" mice, sends them a plan with the location of a "treasure." The mice find the treasure, and after opening the chest with great difficulty, find "a ghost" - the cat Leopold, who urges them to live peacefully together..