Case Closed (1996)

Season 6

Episode 18: The Mysterious Old Man Disappearance Case

While on the bus home, Ran meets an old man who later disappears. Later she finds a MO disk in her purse with secret information about fraud involving several companies. Conan realizes the old man must've been followed and captured. After Sonoko is kidnapped, Conan manages to find out where the culprits are hiding, and saves her and the old man.