Kuroo Tetsurou, a famous hitman in the city of Tokyo. He is known to have no mercy to his targets as he was named as The Grim Reaper. Duke Tsukishima Kei, born with the ability to uncover evil deeds. He is hated by his fellow nobleman but that doesn't stop him from uncovering the evil. Two men with different lives, on one simple assignment made them cross to each others lives. What will happen to them?