At the beginning of "The Crabtree Affair," the reader finds Sir John and his wife strolling along a disused canal, one fine English summer day. They indulge in affectionately ironic conversation, making it obvious that theirs is a long-standing marriage (although as I remember, they also talked that way to each other before marriage---see "Appleby's End"):
Lady Judith: "It's private enough. As we were saying, this country-side seems absolutely deserted. Not a sign of habitation, population, a trace of the modern world."
Sir John: "You're wrong there, Judith. Look south."
"Judith looked south---which was towards what Appleby had called the secondary motor road. All she saw was a momentary glint of light.
"'I think,' she said, 'that I saw the sun reflected from the wind screen of a passing car. Right?'
"'Right as far as you go. What you saw was a silver-grey Rolls-Royce Phantom V.'
"'My dear John, it's terribly vulgar to name cars---particularly astoundingly expensive ones. It's only done by cheap novelists. You must just say: 'a very large car.''
"Appleby received this with hilarity."
Eventually (you knew this was going to happen), the Applebys find a body floating face-down in the scummy canal-water. The quest for the murderer of returned prodigal, Seth Crabtree, proceeds in the leisurely fashion of a Golden Age British manor house mystery. It is leavened, as are all of Michael Innes's novels, with a great deal of erudite wit and conversation. It has not one, but two snobbish butlers, and also features Judith's eccentric great-uncle, Colonel Raven whose life's work-in-progress is the "Atlas and Entomology of the Dry-Fly Streams of England."
If you are a already a fan of Margery Allingham, Edmund Crispin, or Dorothy Sayers, you definitely need to add Michael Innes's mysteries to your reading list. "The Crabtree Affair" is perfect in its class, and you will also learn quite a bit about the English Canal system.
So if you are a person who craves more detailing in an action and adventure, this is the book for you. No lie, you will not be disapointed. Take my word for it.
However, if you can swallow the premise that an obscenely wealthy individual is stealing paranormal objects (including a counting horse, a witch, and a haunted house) with the goal of cornering the market on the supernatural, then founding a new religion and ruling the world after the current dust-up (WWII) is ended, you'll enjoy this story. It has a Grand Guignol climax on the banks of the mighty Amazon River, that includes not only the cab horse, the witch, and the haunted house, but also the phosphorescing ghost of a murdered man.
It also has the strangest motive for murder in all of fiction.
Inspector Appleby is drawn into the Daffodil affair when a cab horse of that name goes missing in wartime London. Daffodil happens to be the favorite 'ride' of Appleby's elderly maiden aunt. Not only is he a gentle, slow-moving steed, he can also answer numerical queries by bobbing his head the requisite number of times, in the manner of the psychic horse, Clever Hans (although Clever Hans used his hoof not his head).
Meanwhile, another Scotland Yard detective named Hudspith is hard at work on the abduction of Lucy Rideout, a young woman with a multiple-personality disorder. He and Appleby converge on the scent when a haunted house in Bloomsbury goes missing.
The detectives follow the trail of the paranormal captives onto a ship bound for South America, posing as psychic Australian sheep ranchers in order to bamboozle the wealthy collector into abducting them, too. Appleby spends his time at sea philosophizing about the gullibility of mankind and persuading his partner Hudspith to fake supernatural visions.
Innes's C.I.D. inspector is more intellectually morose than usual (remember that the author wrote this story in the midst of the war), but his antic streak also emerges, especially when he is persuading the gullible Hudspith to act out yet another phantasmagoric visitation.
"The Daffodil Affair" is vintage Appleby, in spite of its preposterous plot. It shouldn't be the first Innes mystery you read (try "Hamlet, Revenge!" or "One Man Show"), but once you're hooked you won't be able to stop yourself from enjoying it--supernatural fizz, metaphysical speculations, counting horses, and all.