In their world, you either get a soul mark tattoed on your body once you meet your soulmate or you don't. Lee Yoon-hoo found his. His girlfriend of three years, Heo Yeon-wol. But Yoon-hoo wakes up one morning to another soul mark growing on his body. 

She lurks in the shadows, always existing in his dreams. He ignores it, until he can't anymore. They talk. It's the begining of the end, for a second life he isn't aware of.