Case Closed: Season 1, Episode 324
1 - 324: Heiji Hattori's Desperate Situation! (2)
While held at gunpoint, Heiji sends a modified version of the code to Kogoro and asks him to solve it. Conan manages to solve the code.
While held at gunpoint, Heiji sends a modified version of the code to Kogoro and asks him to solve it. Conan manages to solve the code.