Hinako is a surf-loving college student who has just moved to a small seaside town. When a sudden fire breaks out at her apartment building, she is rescued by Minato, a handsome firefighter, and the two soon fall in love.
The prideful archangel Lucifer disobeys God and is cast into the lowest level of hell as a fallen angel. On her way to hell, Lucifer happens to meet a high school girl on Earth named Maria, who helps her. In hell, Lucifer meets Leviathan, and Leviathan explains to Lucifer about The Seven Deadly Sins, the seven demon king rulers of hell. After The Seven Deadly Sins seal Lucifer's powers, Lucifer goes on a journey with Maria and Leviathan to defeat them.
At the end of the second semester of third year of high school, four students are prepared for graduation and feel the ending to their high school life. But that changes a little with the arrival of a transfer student.
