Mouse, a steadfast ally to the protagonist, is captured by a witch-aligned girl and forcibly transformed into a harpy via a machine that enslaves minds. Under the witch’s control, Mouse embraces a temporary antagonistic role, zealously hunting former comrades and chanting demands for their conversion. During a clash with allies, Mouse accidentally dislodges a magical crystal ball—a critical mishap that fractures the witch’s dominance and allows her defeat. After the witch’s demise, the harpy curse lifts, reverting Mouse to their original form. Freed from manipulation, they rejoin the group, resuming their loyal, supportive role with no lasting traces of their coerced actions.