Henry Dilling, a scientist with a devious mind, has offered to sell some research papers on lasers to a secret government department. As the negotiations are about to start, he drops dead of a heart attack. The papers cannot be found. The department has been keeping him under surveillance, and knows he must have hidden them on the day before his death when he somehow managed to leave the house with his girlfriend and avoid the watchers for most of the day.
John Grimster is assigned to question the girlfriend and find the papers. He is a protegé of Sir John Maserfield, the director, but now distrusts and is distrusted by the department since he recently applied to get married to a Swedish girl who then died in a road accident. Grimster thinks the accident might have been engineered on the orders of the director, since foreign wives are regarded as a security risk.
Dilling's girlfriend Lily says that she and Dilling spent the whole of the day before his death at home, and appears to be telling the truth, though Grimster knows it is not true. He finds that Dilling dabbled in hypnotism, and has hypnotised Lily into remembering a false set of events for the day. Grimster tries to hypnotise the girl, but fails to unlock her memory. However, he comes across a colleague who is drunk and hypnotises him; in the trance the colleague tells him that the accident to his fiancée was indeed murder. Grimster contemplates revenge.
Published by Heinemann in 1971 at £1.80 and by Morrow in the USA in 1972 at $5.95, this was the second of the newly realistic and cruel thrillers that became Canning's hallmark in the 1970s, and the first to feature "The Department", which subsequently became "Birdcage".
This is a very good book indeed, quite unlike any of its predecessors and a real pivot in Canning's career. The textbook on hypnotism which is referred to is authentic, and obviously had been studied by Canning in his research. High Grange is fictional, but the Fox and Hounds Inn at Eggesford exists, and is also used as a setting in the third of Canning's Smiler trilogy, The Painted Tent. It is popular with fishing enthusiasts, and fishing expertise figures large in the book.