Two detectives from opposite ends of Japan get pulled into the same case by accident, then have to outthink each other to prove who's the better detective while Kaitou Kid plays them both. The jewel hunt becomes an excuse to watch Conan and Heiji's chemistry crack under real pressure, their rivalry sharp enough to cut through the mystery. This is what happens when the show stops pretending the puzzle matters more than the people solving it.

A blackmail call reaches Kogoro Mouri's detective agency by mistake, dialed to the wrong number. Conan recognizes something familiar in the caller's voice: it resembles that of Heiji Hattori, his old friend and a high school detective from Osaka. The two team up once more to crack the case and recover a stolen diamond worth a fortune. They are not alone in the hunt, though. Kaitou Kid, the infamous master thief, has chosen the same jewel as his next target, so Conan and Heiji must identify the culprit and secure the gem before Kid gets his hands on it. A one-episode mystery OVA built around a three-way chase.