Cold Case Hunting Record

A frozen girl's body, a silver ring engraved with the name of the deceased fifteen years ago, and a red rope that should have disappeared long ago. On the first day the cold case team was established, there were only two members: a genius detective who was sent to the basement, and a down-and-out old drunkard who was lame. What they want to investigate is a series of unsolved cases in which four girls were killed by the same method over the past fifteen years, but no one has ever connected them.