Setsuna Kashiwagi, a downtrodden and cynical soul, finds himself at the edge of a bridge, contemplating a drastic decision. Just then, a enigmatic stranger emerges, proposing a life-altering deal: 10 million yen for his life within a year. Despite initial doubt, Setsuna agrees. The following day, as he awakens from what he believes to be a dream, he is startled to find two enchanting women by his side. These women, Kanna and Rena Kurohime, reveal themselves as demon princesses with a mission to win his heart over the course of a year.