Fate/kaleid liner Prisma☆Illya Movie: Sekka no Chikai

Shirou Emiya inherits Kiritsugu's impossible ideal of saving everyone, but his dying world turns that principle against the one person he cannot sacrifice: Miyu, the girl he has come to love as a younger sister.

When Miyu becomes the key to restoring the world, Shirou rejects the role of impartial hero and chooses her instead. Standing alone against a Holy Grail War, he accepts becoming the enemy of the world if that is what it takes to keep one promise beneath the snow.