Youko Nakajima, a girl yearning for normalcy despite her red hair setting her apart, leads a typical life of compliance until a peculiar man named Keiki proclaims her as his destined ruler from a different realm. Their introduction is interrupted by malevolent creatures known as youma, prompting their escape into Keiki's kingdom. Alongside two classmates, Ikuya Asano and Yuka Sugimoto, they find themselves stranded in a hostile land, forced to navigate its dangers without Keiki's guidance.