Synopsis: Fate/kaleid liner Prisma ☆ Illya Drei 3!!

Illyasviel von Einzbern awakens in a parallel world, distressed and in peril without the support of Miyu Edelfelt or Rin Toosaka. The once lively Fuyuki City lies in ruins, buried in snow, with a colossal crater at its center. Illya searches for signs of human life but finds only the ruins of her home and the absence of her family. Suddenly, Illya is pounced on by Tanaka, a mysterious girl in a gym uniform who has lost all memory. Despite Tanaka's situation, she offers to assist Illya and together they seek refuge in a nearby playground. While hiding from the snow, they get ambushed by an agent of the formidable Ainsworth family. Even though the attacker flees after the initial attack, it becomes apparent that more danger awaits them in the familiar terrain.