Ran, Conan, and Kogoro takes a nice morning walk around the neighborhood. Kogoro buys an energy drink called Kasuman, then a person screams out loud and they rush over just to see a man die and a bottle of Kasuman next to him. Was it poison?

An S.O.S. message in a bottle disrupts Conan's beachside vacation. Can he and his Junior Detective League friends find the young woman they believe to be the note's author?