警視庁の刑事は、特殊なケースを除き、原則的に潜入捜査は許されていない。だが、難事件解決の為、捜査一課の密命で潜入捜査を請け負う私立探偵と助手がいた。これは、並外れた記憶力を武器に難事件に立ち向かうちょっと奇妙な名探偵と、彼に振り回されながらも愛情を持ってアシストするタフでキュートな助手とのコンビが送る、新しい探偵物語。
Arrest rates for the police have dropped significantly. Believing this calls for desperate measures they have against the rules begun to hire a private detective for cases which require undercover work: Toru Oribe, nicknamed Tokage (the Lizard). Unsociable yet brilliant, Tokage is a former cop whose leaving the force is one of the main reasons why arrest rates have dropped, and he smoothly infiltrates criminal circles by taking on various identities. However, his former colleagues treat him with suspicion and resentment over a case two years ago, when he supposedly left his partner to die.
