Sungjong lives in a world where everyone gets a chance to live another life. Legends say it started because of one's good or bad karma, but no one knows for certain. After several lives, he meets someone special...with an infinity symbol, instead of the typical, evergrowing tattoos that show the number of lives. Myungsoo is different. 

Yoongi was just a normal guy, seemingly invisible to society. However, when darkness falls from a strange cloud covering, no one thinks anything of it. It lasts long enough to cause damage, but The Eternal Source know what's really going on, and they randomly pick people to take on The Void, becoming the only ones who will be able to stop it, by traveling to shrines and closing the portals to a parallel existence. If they fail, the world is doomed.