In near-future Japan with ultra-low birthrates, children are treasured but monitored. Santa is banned as dangerous. One snowy December 25th, middle-schooler Sanda Kazushige, descendant of Santa, is attacked by classmate Fuyumura who wants him to find her missing friend, Ono. "Santa, please find my friend." To protect children from adults, Sanda decides to become Santa and fight the adults. Source: Prime Video Note: The first episode received an early screening on 4 July 2025 at Anime Expo in Los Angeles. The regular TV broadcast started on 4 October 2025.