You only live once, they say. So we should make the most out of it. As an outgoing teenager, Yuna signed up into this dark website to a play a game she doesn't even know about. The next day after she signed up, random numbers suddenly appeared in her forearm. She's fine with it but when the game began, her life turned out to be a living hell. Where does the numbers came from and what do they symbolize? When will the game start and what kind of game she signed up?