Conan and Ran accompany Kogoro to the mansion of a client, soft-serve ice cream maker Morikawa Yuzan. Yuzan has cancer and not long left to live, and asks Kogoro to advise him on distributing his legacy. At the mansion are his heirs and sons Moriakwa... (more) Yuichiro, Morikawa Yujiro, and Morikawa Yuzaburo, as well as Oi Hiroki the lawyer and Shito Yuka the chief butler. The brothers won't stop talking about the inheritance, and each one is desperate to get his hands on their father's legacy...