Everyone has the potential to fall to the other side. Meth, marijuana, MDMA—once hooked, there is no turning back. In the shadows of modern Japan, two relentless hounds chase, expose, and capture all manner of drug-related crimes. Their profession is that of narcotics agents, known as Matori, a shortening of the Japanese term for drug enforcement officer. The narrative follows investigators Kusakabe and Saeki as they navigate a dark underworld, their work unearthing the deep-seated darkness of contemporary society in a hard-hitting documentary-style portrayal of drug crime.

The setting is contemporary Japan, where the agents operate under the jurisdiction of the Ministry of Health, Labor, and Welfare. The central characters are the two agents: Kusakabe and Saeki, who serve as the reader's eyes into the devastating impact of substance abuse. The series aims to show how otherwise ordinary people can cross the line, with the agents confronting a wide spectrum of offenders. The case files depict various scenarios of addiction and enforcement, ranging from the confiscation of marijuana to the horrors of hardcore substances like cocaine and heroin. One notable arc involves a teacher who confiscates drugs from a student only to sample them himself, a decision that leads to a rapid and catastrophic descent into more dangerous narcotics. Throughout its run, the manga maintains a grim and cautionary tone, presenting its stories as shocking exposes meant to document the societal damage wrought by the drug trade.