Some time ago, the influential and powerful Toue Inc. purchased the island of Midorijima, Japan, intending to construct Platinum Jail—a luxurious utopian facility. The residents fortunate enough to call it home are the wealthiest citizens in the world. However, the island's original inhabitants were forced to relocate to the Old Residential District; and following the completion of Platinum Jail, they were completely abandoned. "Rib" and "Rhyme" are the most popular games played on the island. Rib is an old-school game where gangs engage in turf wars against one another, while Rhyme is a technologically advanced game in which participants battle in virtual reality. To participate in Rhyme, one must possess an "All-Mate" (an AI that typically resembles a pet), and the match must be mediated by an "Usui." Aoba Seragaki has no interest in playing either game; he prefers to live a peaceful life with his grandmother and his All-Mate, Ren. However, after being forcefully dragged into a dangerous Rhyme match and hearing rumors about Rib players disappearing, all of Aoba's hopes for a normal life are completely abolished.