After a calamity befalls Tokyo, some of the city's survivors find themselves with powerful abilities bestowed on them by colorful tattoos. The city is cordoned off from the world, and its inhabitants isolated. To create peace, the city has been divided into 23 wards, each controlled by a powerful group known as 'Kumi'. Together, these Kumi form the 'Union.' It's rumored that escape from the devastated city is possible, but only for the person who manages to defeat all 23 Kumi.