Chūta, an insular mouse from the island of Yumemishima, arrives at a harbor gravely wounded after fleeing the invasion of the cruel Noroi Clan, who slaughtered many of his island’s inhabitants. He seeks aid to defend his home and the remaining mouse colony from the invading weasels.

He is the younger brother of Shioji, granddaughter of the elder mouse Shuro of Yumemishima. His plea for help is at first met with fear and rejection from the harbor mice, who dread the notorious Noroi. Yet his desperate story ultimately persuades Gamba and Bobo to join his cause and sail back to Yumemishima to confront the Noroi Clan.

Across adaptations, including the original 1975 anime and the 2015 3D CG film, he remains an island mouse who travels to the city seeking help. In every version, his actions set the central plot in motion, spurring the main characters to embark on their adventure against Noroi.