They sold their souls for power—now they have until eighteen to reclaim their humanity.
When childhood friends Ren and Rai make a desperate pact with the demon Diabolo to save Ren’s cousin Mio, they gain incredible supernatural powers—but the bargain comes with a terrifying price. As they approach their eighteenth birthdays, the two discover that those who make pacts with Diabolo begin losing their sanity at seventeen before eventually surrendering their humanity altogether. Now Ren and Rai must use their powers to help other teenagers trapped by the same curse while searching for Mio and a way to escape their own fate.