The TARDIS materialises not far from Paris in 1794 — one of the bloodiest years following the French Revolution of 1789. The travellers become involved with an escape chain rescuing prisoners from the guillotine and get caught up in the machinations of an English undercover spy, James Stirling — alias Lemaitre, governor of the Conciergerie prison.
| Actor | Role |
|---|---|
 William HartnellThe Doctor | The Doctor |
 Carole Ann FordSusan Foreman | Susan Foreman |
 Jacqueline HillBarbara Wright | Barbara Wright |
 William RussellIan Chesterton | Ian Chesterton |
 Keith AndersonRobespierre | Robespierre |
 Jack CunninghamJailer | Jailer |
 Jeffry WickhamWebster | Webster |
 Neville SmithD'Argenson | D'Argenson |
| LLaidlaw DallingRouvray | Rouvray |
| PPeter WalkerSmall Boy | Small Boy |
| JJames CairncrossLemaitre | Lemaitre |
| RRoy HerrickJean | Jean |
 Donald MorleyJules Renan | Jules Renan |
| TTony WallNapoleon Bonaparte | Napoleon Bonaparte |
| CCaroline HuntDanielle | Danielle |
 Edward BrayshawLéon Colbert | Léon Colbert |
| DDallas CavellRoad Work Overseer | Road Work Overseer |
| DDenis ClearyPeasant | Peasant |
| JJohn BarrardShopkeeper | Shopkeeper |
 Ronald PickupPhysician | Physician |
| HHoward CharltonJudge | Judge |
| RRobert HunterSergeant | Sergeant |
| KKen LawrenceLieutenant | Lieutenant |
| PPatrick MarleySoldier | Soldier |
| TTerry BaleSoldier | Soldier |
| JJohn LawPaul Barrass | Paul Barrass |