In the year of our Lord 1363, two suspicious deaths in the infirmary of St. Mary's Abbey catch the attention of the powerful John Thoresby, Lord Chancellor of England and Archbishop of York. One victim is a pilgrim, while the second is Thoresby's ne'er-do-well ward, both apparently poisoned by a physic supplied by Master Apothecary Nicholas Wilton. In the wake of these deaths, the archbishop dispatches one-eyed spy Owen Archer to York to find the murderer.

As the city prepares to celebrate Queen Victoria's golden jubilee, Veronica Speedwell is marking a milestone of her own. After burying her spinster aunt, the orphaned Veronica is free to resume her world travels in pursuit of scientific inquiry - and the occasional romantic dalliance. As familiar with hunting butterflies as she is fending off admirers, Veronica wields her butterfly net and a hatpin with equal aplomb, and with her last connection to England gone, she intends to embark upon the journey of a lifetime.

When young Tyballis discovers her husband has been arrested for murder, she is delighted. As a young orphan coerced to marry her abusive neighbor, she was horribly used. Now is her chance to be rid of him for good and find the confidence she never had. When Tyballis joins forces with the motley network of Andrew’s informers and thieves, they are lured into the dark and dangerous world of medieval London’s political intrigue and back alley slums.

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.

Salisbury, 1226. A young pregnant woman is found tangled in reeds in the river Avon, her identity a mystery. Grieving widow Ela Longespée is determined to succeed her husband as sheriff of Salisbury, and quickly takes charge of the investigation. She soon finds herself in the thick of a neighborhood scandal and a struggle to maintain her authority. With multiple suspects, can she identify the true killer?