Jongin finds himself winning a second chance for reincarnation after death, and the only way out is to possess a sixteen year old Oh Sehun, who has committed suicide. He has to atone for his pre-death sins while finding out what his heinous sins were, or both his, and Sehun's souls would be incarcerated within the afterlife for eternity.

Amidst confusion and a constant nut-case of an Angel Byun Baekhyun on his back, Jongin starts piecing up fragments of both his, and Sehun's past together.