Fate/stay night: Heaven’s Feel II. lost butterfly is a 2019 Japanese anime fantasy film produced by ufotable and directed by Tomonori Sudō. The second installment in the Fate/stay night: Heaven’s Feel trilogy, it premiered in Japan on January 12, 2019 and in the United States on March 14, 2019.
The story is adapted from Heaven’s Feel, the third and final route of the visual novel Fate/stay night. Continuing immediately from the events of Fate/stay night: Heaven’s Feel I. presage flower, the film focuses on the Holy Grail War and the relationship between Shirou Emiya and Sakura Matou, two teenagers participating in the conflict. After Shirou is eliminated from the War as a Master, he continues to seek salvation for Sakura and the other participants. After Saber’s disappearance, Shirou Emiya is effectively eliminated from the Holy Grail War, but intends to continue fighting regardless. After returning from a meeting with Rin Tohsaka, Shirou finds Sakura Matou has been kidnapped by her brother Shinji and the two confront him. Sakura pleads for everyone to stop and Rider heeds her call, revealing Sakura as her true Master. Faced with the reality that he will never be a Magus, Shinji douses Sakura with a potion that makes her lose control of her mana and flees. Archer and Rin attack Sakura, but Rider defends her and starts turning them to stone with her gaze – revealing her identity as Medusa. However, when Shirou is hurt and loses consciousness, Sakura’s grief causes her to injure herself, forcing Rider to stop.
Shirou reawakens in Fuyuki Church, where priest Kirei Kotomine operates on Sakura. He explains Sakura’s body is infested by Zōken Matou’s Crest Worms, which feed on her mana by arousing her.