工藤新一是全国著名的高中生侦探，在一次追查黑衣人犯罪团伙时不幸被团伙成员发现，击晕后喂了神奇的药水，工藤新一变回了小孩！新一找到了经常帮助他的阿笠博士，博士为他度身打造不少间谍武器。为了防止犯罪团伙对他进行报复，新一决定隐姓埋名，暗中追查他们，希望能得到解药。一日，新一 的女友毛利兰来到了阿笠博士的家寻找男友的下落，被小兰撞见的新一情急之下编造了自己名叫江户川柯南，随后柯南寄居在了小兰家。小兰的父亲毛利小五郎是一名私家侦探，新一可以籍着和他一起四出办案一起追查黑夜人的下落。柯南在小学认识步美等小学生，他们一起组织了一个少年侦探团，向罪犯宣战！Shinichi Kudo, a seventeen year old master detective, had it all. He could solve any case brought to his attention and in record time. His girlfriend, Ran, is a karate expert, and her father is a bumbling P.I. who is driven crazy by the fact that Shinichi gets all of the great cases. One day, while Shinichi and Ran are at an amusement park, the pair become separated. Shinichi catches wind of a dirty deal going down, and spies on a pair of men in dark trenchcoats. He's caught and the men use an experimental poison on him, intending to kill him. However, things don't work exactly as planned. When Shinichi comes to, he finds he's shrunken down to the size of a fourth grader. He goes to the goofball inventor that lives next door to him for help, and the inventor agrees to give him a hand. When Ran comes looking for Shinichi, he and the inventor come up with a story saying that Shinichi is a child named Conan Edogawa (Conan as in Sir Arthur Conan Doyle). Ran offers to let "Conan" live with her family while his "family" is away. Shinichi then makes it his mission to one day find the men who poisoned him and get the antidote. Thus concludes the backstory to the series. In each episode, Conan solves a different case in the style of all good detective shows, giving hints to help the viewer try to guess who the villain is, while trying to keep his true identity a secret.
