Accused of treason and stripped of his knighthood, Crispin Guest has survived on the gritty streets of London by reinventing himself as The Tracker, an investigator for hire who can locate lost objects and uncover secrets. When the merchant Nicholas Walcote hires Guest to investigate his young wife Philippa for adultery, he discovers an underground world of danger and dirty dealings. Philippa is indeed hiding something—but she's not the only one. Walcote himself is rumored to possess a holy relic so powerful that some would even kill for it.

The much-feared and hated Eudo - the Lord Bishop of Winchester's clerk - is bludgeoned to death in Pershore Abbey and laid before the altar in the attitude of a penitent. Everyone who had contact with him had reason to dislike him, but who had reason to kill him? The Sheriff of Worcestershire's thief taker, wily Serjeant Catchpoll, and his new and unwanted superior, Undersheriff Hugh Bradecote, have to find the answer. And as the walls of the abbey close in on the suspects, the killer strikes again....

It’s 1924, and Blix Windway has made a career out of her wanderlust, giving lectures to ladies’ groups about everything from the flora of the American desert to the beauty of the Swiss Alps, but she needs new material for her talks. She strikes what seems to be an ideal agreement with an eccentric older lady. Blix will be her travel companion during a journey to Egypt, helping to smooth the way through customs and coordinate sightseeing tours.

Lord Edgington of Cranley Hall has some living to do. The next item to cross off on his list of grand ambitions is a serene balloon flight above his palatial estate. But, after a man falls to his death, the pleasant pursuit is interrupted, and the esteemed detective suspects foul play. With the help of his hapless grandson, their loyal golden retriever and a couple of parachutes, Lord Edgington must solve the murder before the meddlesome police arrive to take control of the case. But, when all of the suspects seem like such nice chaps, it's awfully difficult to spot a killer.

Hugh of Singleton, fourth son of a minor knight, has been educated as a clerk, usually a prelude to taking holy orders. However, feeling no certain calling despite a lively faith, he turns to the profession of surgeon, training in Paris and then hanging out his sign in Oxford. A local lord asks him to track the killer of a young woman whose bones have been found in the castle cesspit. She is identified as the impetuous missing daughter of a local blacksmith, and her young man, whom she had provoked very publicly, is in due course arrested and sentenced at the Oxford assizes.