It's summer of 2021. After the defeat of the Smileslaughter a year prior, the world has slipped into lawlessness as warlords and crime bosses have emerged from the shadows. The job of a bounty hunter has become very lucrative, attracting many young people. An up-and-coming hunter named Zehiro Kahana is sent after a weapons dealer, but winds up in a search for an ancient gemstone, which only the bravest warriors can hold in their hands.