Follow the Vanished Diamond! Conan & Heiji vs. Kid!

This OVA is a post-story for The Private Eyes' Requiem.

Situation
A mysterious package comes in for Kogoro. Moments later, a diamond thief with a voice similar to Heiji's accidentally calls the Mouri Detective Agency asking for a ransom. Soon realizing that he has dialed the wrong number, the caller hangs up, but not before a familar voice says "Good morning!" on the other line. Conan deducts that the caller had meant to dial a similar number, and calls Heiji over to mimick his voice and call a list of similar numbers. Only one person responds; Yuwatsume. The detectives approach him and question him to discover that the man had paid 10,000,000 yen to retrieve his stolen jewel. After realizing the meager ransom, which was a tenth of the value of the diamond, it is discovered that the returned gem was a fake.

Resolution
Hide= |-|Show= Conan and Heiji discover the culprit after finding the contents of Kogoro's mysterious package; a Yoko Okino alarm clock. The alarm clock's "Good morning!" was what was heard on the other line. After questioning Kogoro, they discover that only 200 alarm clocks were produced and sold only to those in the Yoko Okino fan club. They corner the culprit on the bridge. The culprit threatens to throw the jewel into the ocean, but accidentally drops his Yoko Okino clock into the sea. Kaitou Kid catches the thrown jewel and returns it to the owner the next day.