Illyasviel "Illya" von Einzbern wakes up in a parallel version of Fuyuki City, disoriented and alone. She discovers her home in ruins, with a large crater smack dab in the middle of town. With snow falling in the middle of summer, the little elementary schooler is befuddled, not knowing where her pals or her wand Ruby are. As she approaches the ruins of her home, she is abruptly confronted by an amnesiac girl. The enigmatic girl, dressed in a gym uniform as the chilly temperature sets in, has no idea where she is or why she has arrived. However, this stranger, known as Tanaka, appears to know where Rin Toosaka, Miyu Edelfelt, and the others are.