24-hour surveillance of ex-lover's activities. A handsome demon king and an unlucky hero from a previous life. Despite his bad luck, Yuuki Yuta lives an ordinary life. One day, a handsome transfer student, Mazaki Rei, arrives at Yuta's school. Although it should be their first meeting, Rei's sense of distance from the very first day is a bit strange. When Yuta asks him why, he learns that Rei is the Demon King and that Yuta was a former hero in his previous life, And they were even lovers...! Until Yuta's curse is lifted, he and the Demon King begin a 24-hour, indefinite life of surveillance! 不幸体質ながらも平凡に暮らしていた勇木ユウタ。 最近は誰かが泣いている不思議な夢を見るようになっていた… そんなある日、ユウタの前に突然、転校生の間崎レイが現れる。 初対面なのに何故か距離感がバグっているレイを不思議に思っていると、 ユウタの前世は異世界で勇者。自分は魔王で、さらには恋人同士だったと告げられて…！？