Conan, Ran and Sonoko arrive at the trendiest dating spot. They find an old woman, Hal Kamogawa, sitting on a bench with an anxious look on her face, and try to talk to her to see if she is lost. Then a man arrives. Conan and his friends think he is Hal's son from his appearance, but he, Joji Kazama, says he is her lover. Sonoko, seeing that Hal is a very wealthy woman, considers the possibility that Kazama, who is as old as her son, approached her for her money, and tries to give her some advice, but she is given the cold shoulder...