The Trio Alliance's Summer Vacation Special Mystery - The Tale of the Mysterious Box

Umi Tenjin

Miiko Yamada (voice)

Atsushi Kisaichi

Kenta

Kotono Mitsuishi

Mama

Akiko Yajima

Mamoru Yamada

Ai Nagano

Yuuko Ogawa

Kumiko Watanabe

Mari Shimura / Ryuuhei's Mother (voice)

Naritoshi Tajitsu

Papa

Taiki Matsuno

Ryuuhei Eguchi / Yuuko's Little Brother (voice)