Kudo Shinichi was a senior high school student and also high school detective. Everything ran well until he met an upper-class villain in amusement park that he visited with his girl friend, Mouri Ran. He tried to record a transaction between the villains but was seen by one of them. Then he was forced to drink a pill, Apotoxin 4869 which made his body smaller like an elementary school student. After getting help by Professor Agasa that lived next to his house, he finally pretended to be an elementary school student named Edogawa Conan and stayed at Ran's house. Ran's father, Mouri Kogoro was a detective. He thought that if he stayed at his house, many informations include the black organization'd come. Then, he got through the next days with making Kogoro more famous with his skill as Edogawa Conan.
How's the end? Dunno. But I hope Shinichi won't be killed (though I heard he'd).