Conan hears two women scream while on the way to the park with Genta and Mitsuhiko. They go to the house where they heard the screams, where they see Hirasawa Kaori and Hirasawa Seiko, who have fallen down some stairs. From their conversation with Hirasawa Ryoji, who arrives shortly afterwards, they learn the women are his wife and mother-in-law, and he is the family`s son-in-law. It seems as though all they do is cause trouble for Ryoji. Later, Conan and his friends see Ryoji struggling near the park. According to Ayumi, her neighbors have been talking about the Hirasawa family...