- You may be looking for the titular house at 64 Carlysle Street.
The Doctor, Steven and Dodo are on the trail of a time-travelling alien named Roztoq, who is from Quinnis. They find that he has made the acquaintance of Annabel Greystone, the daughter of Lord Geoffrey Greystone, posing as the Marquis of Rostock. The Doctor manages to get an invitation to visit Lord Greystone house at 64 Carlysle Street, and Steven accompanies him as his chauffeur. Dodo arrives at the house as well, applying for a job as maid.
Lord Greystone invites "Rostock" to the house to meet with the Doctor. The Doctor confronts Roztoq. Meanwhile, downstairs in the servants' hall, the old butler, Mr Golightly, has passed away, causing the cook, Mrs Doyle, to go into hysterics.
Upstairs, Roztoq holds out his hand, which contains a silver thing. It shoots across the room, hitting Annabel. It possesses and controls Annabel, bringing her downstairs. She/it points at the screaming Mrs Doyle, and silences her.
The Doctor and the rest of the upstairs party follow, and the Doctor lectures the alien possessing Annabel, telling him that by leaving Quinnis he has damaged this reality. The Doctor then approaches Annabel and encourages Annabel to fight the possession. She does, and it leaves her.
Steven punches Roztoq. The Doctor and his companions depart, and an ambulance arrives for Mr Golightly and Mrs Doyle.
- First Doctor
- Steven Taylor
- Dodo Chaplet
- Inspector Brown
- Sergeant Dunston
- Alice Fittle
- Thomas Greene
- Annabel Greystone
- Lady Edith Greystone
- Lord Geoffrey Greystone
- Matilda Jenkins
- Emily Trott
- Ronnos is the prison moon of Quinnis.
- This story is told in the form of police reports given by Lord Greystone and the members of his household.