Yoshitaro Katayama (Masaki Aiba) became a police detective after having followed the will of his father who had been known as a great detective. However, Yoshitaro can never step into murder scenes because he faints whenever he sees blood, and criminals are able to easily slip away because he is afraid of heights. He also has phobias of women and ghosts. Moreover, he hates to doubt people more than anything, so he happens to believe whatever people say. Thus, Yoshitaro has tried, in vain, to quit his job a number of times in the past, but his brother Hiroshi (Naohito Fujiki), who loves mystery novels, and his super active sister Harumi (Aya Omasa) always manage to convince him to remain as a detective.

One day, hopeless Yoshitaro finds a calico cat that somehow understands what people say and sometimes shows great reasoning power. With the help of strange hints given by this cat, Yoshitaro luckily succeeds in solving the cases.

Yoshitaro Katayama est détective au sein de l'équipe d'enquête n°1 de la police métropolitaine de Tokyo. Il est devenu détective à cause de la dernière volonté de son père mourant qui était aussi un détective, mais Yoshitaro veut maintenant quitter son emploi parce qu'il ne supporte pas le sang, a peur des fantômes et est timide avec les femmes. Yoshitaro rencontre alors un chat extraordinaire nommé Holmes, capable de comprendre les mots humains et possédant des capacités de raisonnement déductif accrues. Yoshitaro et Holmes s'associent alors pour résoudre des cas difficiles à résoudre...

刑警该具备的素质中，片山义太郎（相叶雅纪 饰）可谓十个有九个都不具有。该有的果断、勇气、大胆到了片山身上成了恐高症、幽灵恐惧症等各种标注胆小的弱点。片山的弱点让他深刻的认识到自己居然是警察是件多么不合理的事情。于是整日想着递交辞呈的片山却因为狂热的推理爱好者，自己的哥哥片山浩史（藤木直人 饰）和果断的妹妹片山晴美（大政绚 饰）劝他不要放弃警察这个职业而止步，不敢抗拒二人的片山只得咬牙坚持着。直到有一天，事情发生了转机，在路上，片山邂逅了一只奇异的三色猫。这只猫开启了他之后如有神助的破案之旅……

인간의 말을 이해하고 추리력이 강한 삼색 털 고양이 홈즈와 조금은 덜렁거리는 형사가 만나 사건을 해결하는 이야기.