The TARDIS arrives in 1925 England where the Doctor ends up playing in a local cricket match due to a case of mistaken identity. The travellers accept an invitation to a masked fancy dress ball, but events take on a more sinister tone as murders are perpetrated at the country home of their host, Lord Charles Cranleigh.
| Actor | Role |
|---|---|
 Peter DavisonThe Doctor | The Doctor |
 Matthew WaterhouseAdric | Adric |
 Sarah SuttonNyssa / Ann Talbot | Nyssa / Ann Talbot |
 Janet FieldingTegan Jovanka | Tegan Jovanka |
 Michael CochraneLord Cranleigh | Lord Cranleigh |
 Barbara MurrayLady Cranleigh | Lady Cranleigh |
 Gareth MilneThe Unknown / George Cranleigh | The Unknown / George Cranleigh |
 Moray WatsonSir Robert Muir | Sir Robert Muir |
 Ivor SalterSergeant Markham | Sergeant Markham |
 Andrew TourellConstable Cummings | Constable Cummings |
| AAhmed KhalilLatoni | Latoni |
| BBrian HawksleyBrewster | Brewster |
| TTimothy BlockTanner | Tanner |