One day Mori Kogoro's private detective agency receives a blackmail call. It turns out that the caller has dialed the wrong number. Conan is able to identify the voice on the phone, it's similar to that of his old friend Heiji, who's also a high school detective but in Osaka. They join once again forces to solve the case and find the jewel which was stolen.
But they are not the only ones who are after the jewel. The notorious master thief Kaitou Kid has taken an interest in this piece, which is worth 100,000,000 Yen, as well and now it's up to Heiji and Conan to be the first to find the culprit and acquire the jewel.
This is definitely the weakest of the Detective Conan OVAs for me, thus far. The story starts off somewhat interesting, but eventually trails off. Despite Kaitou Kid being featured in the title, and on the cover, he barely shows up, and what we're left with is an empty story where things tend to happen without any real reason, and the mystery that's solved is simple and boring. There's a few funny moments which work well enough, but that's not good enough to fill an entire episode with. By the end, there's no real conclusion to the story, and things just kind of end with there
being no actual ending.
The characters are still just as interesting as they are in the show normally, the art is passable, as is the soundtrack. Everything besides the story is passable, but overall, this is a really weak, tepid episode, which doesn't offer up anything significant to the overarching Detective Conan storyline, and also fails to be an interesting stand-alone story. If you're a fan of the show and have a need to watch every episode, feel free to watch it, but for everybody else, I'd say that this one is definitely skippable.