Case Closed: Conan and Heiji and the Vanished Boy

Meitantei Conan: Conan to Heiji to Kieta Shounen

FINISHEDOVA★ 6.8

Conan and Ran are visiting Heiji and Kazuha in Osaka but while they are touring around they come across a group of three kids that look like Ayumi, Mitsuhiko, and Genta. The group are looking for their missing friend and Conan agrees to help. (Source: Anime News Network)