Mayumi Esaka

Mayumi is concerned for Satoshi and cooperates with the detectives trying to locate him. Her willingness to discuss her friend's behavior and the group's shared experiences helps establish what Satoshi may have been trying to communicate.

She behaves like an ordinary elementary-school child rather than a trained investigator. Her importance comes from knowing Satoshi personally and therefore understanding details that adults unfamiliar with the children could easily overlook.

Mayumi has no unusual abilities. She is an ordinary seven-year-old elementary-school student.

Her useful contribution to the investigation is her familiarity with Satoshi, his friendships, and the places the children know around Osaka. This contextual knowledge helps Conan and Heiji interpret clues connected to the missing boy.

Mayumi appears in Conan, Heiji, and the Vanished Boy, an original-video story set in Osaka. Conan and Heiji become involved when Satoshi disappears, leaving behind clues that require knowledge of his life and surroundings to interpret.

Mayumi, Mikihiko, and Kenta provide information about their missing friend while Conan and Heiji follow the trail.

Satoshi has been kidnapped after becoming involved in circumstances connected to two bank robbers. Conan and Heiji decipher his clues, locate him at his former home, and help bring the kidnapping to an end.

Satoshi Moriguchi is Mayumi's friend and the missing child whose disappearance drives the OVA's investigation.

Mikihiko Yagi is one of Mayumi's fellow elementary-school friends.

Kenta Oosawa belongs to the same group of children as Mayumi, Mikihiko, and Satoshi.

Conan Edogawa questions the children and uses what they know about Satoshi to help trace him.

Heiji Hattori investigates Satoshi's disappearance alongside Conan.