An Esper is someone with supernatural abilities, but the more they use their powers, the greater the risk of them going out of control. In this world, there are Guides who can calm such Espers. Won-woo, a soldier and awakened Guide, otherwise known as “purifier”, was living in a world devastated by war. After losing all his comrades, he suddenly finds himself transported to a parallel world through a mysterious thick fog. Won-woo encounters his dying self beyond the thick fog and is given the opportunity to live as his counterpart in another world. “I hope you don't live a meaningless life filled with regret...” In this new world he encounters, surprisingly, all his deceased comrades are alive. Won-woo goes to find them and uses his abilities to help them, and in the process, he encounters the ruler of the North, Gye Yoon. “It's because of those eyes. Those eyes that are so similar.” But strangely, every time he sees him, someone else comes to mind...