Sing a Bit of Harmony tells the story of the beautiful and mysterious Shion who transfers to Keibu High School where she quickly becomes popular due to her open-hearted personality and exceptional athletic talent...but she turns out to be an AI in the testing phase!

Shion's goal is to bring chronic loner Satomi "happiness." However, her strategy is something no human would expect: she serenades Satomi in the middle of the classroom. After finding out that Shion is an AI, Satomi and her childhood friend, engineering geek Touma, steadily warm up to the new student. Along with the popular and attractive Gocchan, the strong-willed Aya, and judo club member "Thunder," they become more and more moved by Shion's singing and earnestness even as her antics bewilder them. But what Shion does for Satomi's sake ends up involving them all in some serious pandemonium. Get ready for the heartwarming story of a not quite market-ready AI and her classmates!

(Source: Funimation)

The film was pre-screened in Scotland on October 2, 2021 at Glasgow Film Theatre. The official release in Japan was on October 29, 2021.