Mingyu is a ruthless mafia, a man who has never shown weakness. But there's one heart he wants to protect with all the power he possesses. Wonwoo, a gentle soul who's accidentally dragged into a world he never wanted. Unknowingly, he finds himself caught up in the dangerous mafia world, and in the process, falls in love with the man who's slowly destroying the world he once knew. Between love, misunderstandings, and inevitable conflict, Mingyu and Wonwoo must face trials that will test their love. Will they survive, or will the differences in their worlds tear them apart?

"Please let me go when the rain stops." Mingyu never knew that one kiss would be their last moment borrowed from a world that was already fading. A soft, slow heartbreak between two souls who were never meant to end-but did. Because love doesn't always stay. But sometimes, it leaves letters behind.