Iwano Hiroyuki is a high school teacher living in Tokyo with his loving wife and newborn daughter. Trusted by his students, he believes he’s living an ordinary, everyday life… Until he wakes up naked and imprisoned. Standing over him is a stranger who calls herself Kako, a woman who claims to know Iwano. Slowly but surely, Kako causes Iwano’s life to come crashing down around him. Believing her actions are rooted in his past, Iwano heads to Osaka, where he spent his university years, to trace the long-forgotten truth…