Uta — the most beloved singer in the world. Her voice, which she sings with while concealing her true identity, has been described as “otherworldly.” She will appear in public for the first time at a live concert. As the venue fills with all kinds of Uta fans — excited pirates, the Navy watching closely, and the Straw Hats led by Luffy who simply came to enjoy her sonorous performance — the voice that the whole world has been waiting for is about to resound.

Kakeru, a former elite runner at high school, is chased for stealing food. He is saved by Kansei University student Haiji, who is also a runner. Haiji persuades Kakeru to live in the old apartment "Chikuseisou" where he plans to team up with fellow residents to enter Hakone Ekiden Marathon, one of the most prominent university races in Japan. Kakeru soon finds out that all of the residents except for Haiji and himself are complete novices.

This story revolves around a spirited, carefree boy named Kazuma Harukaze, who lives with his little sister Sakura and his horse Lovely on a farm within sight of Mt. Fuji. One day, a "meteor" lands nearby, and it turns out to be Hinkeeru — a messenger from Muzanda who has come to warn Earth of a grave danger — and a robot horse named Robony.

Eleven-year-old Chizuko Mikamo is a victim; she is aware that her cruel relatives have been slowly poisoning her, but she can't do anything to escape her fate except starve herself. Luckily for her, the infamous thief, Twenty Faces, has arrived to steal her household's most valuable treasure: Chizuko herself. Alongside Twenty Faces, Ken, Skipper and the rest of the gang, Chizuko travels to exotic lands and strange places in search of valuable treasure. But, as she soon discovers, there's much more to the mysterious Twenty Faces than she could ever have bargained for.