Conan and Kogoro see a patrol car parked in front of the apartment building they happen to pass by. Inside the building, a woman who lives alone was found dead. Three sets of fingerprints were found at the crime scene. The first set belongs to the man she was dating, and the second set belongs to the owner of the bar she worked at. The police have no record of the final set. Since there are no signs of forced entry, the police believe she was killed by an acquaintance