Case Closed: Conan and Heiji and the Vanished Boy

Case Closed: Conan and Heiji and the Vanished Boy, released in 2003, is an original video animation produced by Shogakukan-Shueisha Productions as a spin-off of the long-running Detective Conan franchise. Created by Gosho Aoyama, the series follows the high school detective Shinichi Kudo, who is transformed into a child and adopts the alias Conan Edogawa to solve complex criminal cases. This specific OVA was produced to satisfy the high demand for crossovers featuring Heiji Hattori, the clever detective from Osaka who serves as one of Conan's most prominent rivals and allies.

The animation reflects the aesthetic and narrative conventions of the early 2000s era of the series, maintaining the mystery-solving structure that defined the franchise's success in Weekly Shonen Sunday. While the design and character models adhere to the established style guide provided by the studio, the OVA format allowed creators to experiment with slightly more self-contained, lighthearted stories outside the primary manga canon. It was received as a welcome addition for dedicated fans, reinforcing the dynamic between the intellectual leads while providing a bridge between the feature-length theatrical releases.