Foyle must find out if there was a traitor within the SOE after Hilda Pierce is shot in an attempted assassination.
| Name | Type | Role | |
|---|---|---|---|
| Henry Garrett | Actor | Neville Smith | |
| Colin Connor | Actor | Doorman | |
| Elliott Andrews | Actor | Young Miles Corrigan | |
| Katherine Press | Actor | Sophie Corrigan | |
| Conleth Hill | Actor | Sir Ian Woodhead | |
| James Garnon | Actor | Eric Caplin | |
| Leo Gregory | Actor | Damian White | |
| Rupert Vansittart | Actor | Sir Alec Myerson | |
| Darcey Martindale | Actor | Young Sophie Corrigan | |
| Jeremy Swift | Actor | Glenvil Harris | |
| David Ericsson | Actor | Kenton | |
| Gary Sefton | Actor | DI Henry Skinner | |
| Daniel Weyman | Actor | Adam Wainwright | |
| Tim McMullan | Actor | Arthur Valentine | |
| Serge Soric | Actor | Arkady Kuznetsov | |
| Daniel Peacock | Actor | Blakey | |
| Julian Lewis Jones | Actor | James Stafford | |
| Ellie Haddington | Actor | Hilda Pearce | |
| Serge Hazanavicius | Actor | Luc Tellier | |
| Hermione Gulliford | Actor | Elizabeth Addis | |
| Honeysuckle Weeks | Actor | Samantha Wainwright | |
| Nick Caldecott | Actor | Peter Hawtrey | |
| Ferdy Roberts | Actor | Chief Supt. Alan Usborne | |
| Ronnie Fox | Actor | Derek Gates | |
| Jesse Fox | Actor | Miles Corrigan | |
| James McGregor | Actor | Agent | |
| Emma Fielding | Actor | Joyce Corrigan | |
| Simon Hepworth | Actor | Doctor Parsons | |
| Michael Kitchen | Actor | Christopher Foyle | |
| Tony Clay | Actor | Rex Carter |