Etou Kai may look like a squeaky-clean kid, but the Greater Kanto Narcotics Control Division's new investigator hides a violent alter ego and a dangerous past.

With his stoic partner Kurabayashi Hal, Kai is assigned to track down and stop the distribution of Dragon Speed, a dangerous new drug. But Ryuugen, the syndicate trafficking the drug, is almost impossible to infiltrate. Add street violence and a jurisdiction war with the Meguro Police into the mix, and it looks like Kai's in for some very long days at the office.