Chan is faced with suspects in a stolen atomic bomb formula case, that are being killed with bullets that are not fired from a gun.
| Actor | Role |
|---|---|
 Sidney TolerCharlie Chan | Charlie Chan |
 Fortunio BonanovaInsp. Luis Carvero | Insp. Luis Carvero |
 Benson FongTommy Chan | Tommy Chan |
 Robert Emmett KeaneAlfred Wyans (as Robert E. Keane) | Alfred Wyans (as Robert E. Keane) |
 Willie BestChattanooga Brown | Chattanooga Brown |
 Carol HughesMarguerite Fontain | Marguerite Fontain |
 Marjorie HoshelleCountess Irena Masak | Countess Irena Masak |
 Barton YarboroughJoseph Brandish | Joseph Brandish |
 George MeekerEdmond Slade | Edmond Slade |
 Don CostelloCharles Masack | Charles Masack |
 Charles TrowbridgePrentiss | Prentiss |
| MMildred BoydJosephine | Josephine |
 Barbara Jean WongIris Ling (as Jean Wong) | Iris Ling (as Jean Wong) |
| DDonald D. TaylorWalter Dorn (as Donald Dexter Taylor) | Walter Dorn (as Donald Dexter Taylor) |