When a reporter is killed under mysterious circumstances, the political cartoonist on his paper begins to investigate on his own. He finds that a vengeful industrialist may be trying to manipulate an international peace conference to stage a bombing attack on London.
| Actor | Role |
|---|---|
 Charles FarrellBriant Gaunt | Briant Gaunt |
 Margaret VynerMary Stevens | Mary Stevens |
 Fritz KortnerMinister Peters of Grovnia | Minister Peters of Grovnia |
 Danny GreenSocks, American Henchman | Socks, American Henchman |
| WWallace EvennettSmith, Bowler-hat Henchman | Smith, Bowler-hat Henchman |
| MMonti DeLylePierre, Knife-throwing Henchman | Pierre, Knife-throwing Henchman |
 Dino GalvaniTony, Slender Henchman | Tony, Slender Henchman |
| AArthur FinnMac, Newspaper Editor | Mac, Newspaper Editor |
 Laurence HanraySir George, Lead Conspirator | Sir George, Lead Conspirator |
| AArthur GomezBaron von Kleisch, Delegate | Baron von Kleisch, Delegate |
 Raymond LovellHarris | Harris |
| EEvan JohnDr. Marsh | Dr. Marsh |
| RReynes BartonConference President | Conference President |
| TTerence O'BrienSecret Agent Fearns | Secret Agent Fearns |
| DDennis Val NortonVronsky, Peters' Aide | Vronsky, Peters' Aide |
| BBilly BrayBanks | Banks |
| SSydney KingGraham Stevens | Graham Stevens |
 Andreas MalandrinosZadek | Zadek |
| VVictor TandyGroves | Groves |