Kudo Shinichi is a seventeen year-old high school detective whom people call the "Modern Sherlock Holmes." However, one night after a date with his childhood sweetheart, Ran, Shinichi witnessed an illegal trade and, caught off his guard, was knocked unconscious and fed a drug that was supposed to kill him... but we woke up and found himself shrunken to a seven year-old. In order to track down the men who did this to him, Shinichi hid his identity and lived with Ran, whose father happened to be a hopeless detective, and with that came a series of murders and mysteries that he must solve.
江户川柯南原名叫工藤新一,是一个高中生名侦探,再一次追查一个穿黑衣歹徒行径时,被设计强迫吃下毒药而致身体缩小成一个小学生模样,为了使自己身体恢复原状,计诱歹徒现身找到解药,工藤新一于是开始设法隐藏身份,有一天他在阿笠博士的家中恰好看到了书架上『江户川乱步』全集,而他爸爸又是『柯南道尔』的书迷,于是灵感一动,就以『江户川柯南』之名来掩饰身份。并住进女友小兰家里,想找出那些害他变小的黑衣人。又结识吉田步美等人,组成少年侦探团。