As a war rages on between a machine-based empire and a magic-focused empire, a witch and a soldier meet and fall in love. Will their romance bring an end to their nations' conflict?

What is the true identity of the solitary Raven Consort? The Raven Consort is a special consort living deep in the inner palace who, despite her title, does not perform nighttime duties for the emperor. Some who have seen her say she has the appearance of an old woman, while others describe her as a young girl. The Raven Consort's name is Shouxue. She has the ability to use mysterious arts and will accept any favor asked of her, whether it is to find something lost or to curse someone to death. The current emperor, Gaojun, visits her one night to ask a favor. Their meeting exposes a secret that will turn history on its head...

The story revolves around Haruka Nanase, a boy who has always loved to be immersed in water, and to swim in it. Before graduating from elementary school, he participated in a swimming tournament along with his fellow swimming club members, Makoto Tachibana, Nagisa Hazuki, and Rin Matsuoka. After achieving victory, each of the boys went their separate ways. Time passed, and in the middle of their uneventful high school lives Rin appears and challenges Haruka to a match, showing Haruka his overwhelming power. Not wanting it to end like this, Haruka, gathers together Makoto and Nagisa once again and brings a new member named Rei Ryugazaki to create the Iwatobi High School Swimming Club in order to defeat Rin.