For nights, disturbing noise comes from an upstairs flat. Lee Don decides to go up and he sees there an old man, a young girl, and a black cat. But Lee Don discovers the next day the flat is completely deserted. A cat's inards, however, are left behind.

Lee Don tells this to Wisely, famous for his adventures. Wisely suspects the black cat as the culprit. So he sets out to catch the cat with a very talented dog. The cat's tail is broken in a fight. Everybody is astounded when the laboratory reports the tail shows the cat is at least 60 years old--no cat is supposed to live that long.