In Towa no Yūgure, Akira Himegami awakens from a 200-year cold sleep to discover that the world has drastically changed, now ruled by an organization called Owel. Prior to his long slumber he had confessed his love for Towasa Ōmaki, but in this future, Akira also meets Yūgure, an android who proposes marriage to him. Driven by the belief that Towasa may still be alive, Akira embarks on a journey to find her ‒ with Yūgure accompanying him.