They've been fated together but hardly know each other. Riku and Aiya fall deeper in love and as winter approaches they decide to go back to Aiya's village where they get better acquainted with one another.
Everything happens too fast for Riku. Too soon, Aiya is pregnant, rushing Riku to propose. He wants nothing more than to be with her but finds himself unworthy. This puts distance between them and an air of darkness takes hold of their relationship.
Aiya begins having dreams of the fire demon who sought to claim her for himself. She becomes seemingly possessed by something wicked, devastating Riku. Desperate for an answer, he enlists the help of his older sister who informs him he will have to travel through The Underworld to save Aiya with the man who fell in love with her first.