Detective Umon’s services are called upon when ronin Yaichiro is killed with a peculiar weapon, a stone wrapped in a towel.
| Actor | Role |
|---|---|
 Ryutaro OtomoNot listed | Not listed |
 Kōtarō SatomiNot listed | Not listed |
 Eitarō ShindōNot listed | Not listed |
 Satomi OkaNot listed | Not listed |
 Hiroko SakuramachiShizu | Shizu |
 Kikuko HojoFumi | Fumi |
 Kyoko AoyamaNami | Nami |
 Mikijiro HiraNot listed | Not listed |
| IIkkō ŌkuniNot listed | Not listed |
| SShinnosuke OgataNot listed | Not listed |
| IIchiro FukuiNot listed | Not listed |
 Itoshi YumejiNot listed | Not listed |
 Koishi KimiNot listed | Not listed |
 Sonosuke SawamuraNot listed | Not listed |
 Yataro KurokawaNot listed | Not listed |
 Michitarō MizushimaNot listed | Not listed |
 Shunji SakaiNot listed | Not listed |