The Marlow family, less their father and Giles, who are away at sea, spend their first Christmas at Trennels, the country estate they inherited following the death of their cousin Jon in an aeroplane accident.

Eldest sister Kay is down from Oxford and spends most of her time closeted in the house's library and Rowan is preoccupied with her new role as farm manager.

Snowed in at Trennels and spurred initially by Ginty's school project on the Brontë sisters' fantasy writings, they invent a swashbuckling story set in the imagined lands of Angora and Exina.

The fantasy created by the four youngest Marlow children (twins Nicola and Lawrie, Ginty and Peter) and their friend Patrick Merrick, takes up three chapters of the book.

Alarmed, Nicola knocks it from his hand, where upon it hits a table and is discharged, bringing their activities to adult attention, in the form of the Marlow's sister Rowan.