On a cold February night in Regency London, a dark curtain falls on the Sans Pareil Theatre following the death of April Clare, a promising young actress, whose body is found in mysterious circumstances. Detective Stephen Lavender and his dependable deputy, Constable Woods, quickly discover that nothing is quite as it seems. As successive mysteries unfold, they soon realise that it is not only the actors from the Sans Pareil who are playing a part.

Northamptonshire, 1810: As a new canal network snakes across the landscape, a vicious mob stakes its claim to the county. Every local constable is out on the hunt for the ruthless Panther Gang. When an elderly man is robbed and murdered in sleepy Middleton, the beleaguered magistrates send for help from London's Bow Street Police Office.

Let the wicked be ashamed, and let them be silent in the grave. These ominous words, slashed from the pages of a book of Psalms, are the last threat that the darling of London society, Sir Edward Grey, receives from his killer. Before he can show them to Nicholas Brisbane, the private inquiry agent he has retained for his protection, Sir Edward collapses and dies at his London home, in the presence of his wife, Julia, and a roomful of dinner guests.

London, 1812: Treacherous gangs roam the capital, and not even the Palace of Westminster is safe. When Detective Stephen Lavender is called in to investigate a highway robbery and a cold-blooded murder, both the cases take a dangerous and disturbing personal twist.

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.

As "Sherlock Holmes, consulting detective," Charlotte Holmes has solved murders and found missing individuals. But she has never stolen a priceless artwork - or rather, made away with the secrets hidden behind a much-coveted canvas. But Mrs. Watson is desperate to help her old friend recover those secrets and Charlotte finds herself involved in a fever-paced scheme to infiltrate a glamorous Yuletide ball where the painting is one handshake away from being sold and the secrets a bare breath from exposure.

London, 1812. At a fashionable address in leafy Mayfair, a far cry from Detective Stephen Lavender’s usual haunts, a man is found dead in his room. He has been brutally stabbed, but the door is locked from the inside, and the weapon is missing. The deceased is David MacAdam, an Essex businessman with expensive tastes. As Lavender and Constable Ned Woods travel between London and Chelmsford seeking to understand MacAdam’s final hours and unearth the grisly truth, they uncover a tangled web of deceit behind his stylish facade.

In Grimsgrave Hall, enigmatic Nicholas Brisbane has inherited a ruined estate, replete with uncanny tenants and one unwanted houseguest: Lady Julia Grey. Despite his admonitions to stay away, Lady Julia arrives in Yorkshire to find Brisbane as remote and maddeningly attractive as ever. Cloistered together, they share the moldering house with the proud but impoverished remnants of an ancient family: the sort that keeps their bloodline pure and their secrets close.

After her foray into murder investigation, Lady Kiera Darby must journey to Edinburgh with her family so that her pregnant sister can be close to proper medical care. But the city is full of many things Kiera isn't quite ready to face: the society ladies keen on judging her, her fellow investigator (and romantic entanglement) Sebastian Gage, and ultimately, another deadly mystery.

With her inquisitive mind, Charlotte Holmes has never felt comfortable with the demureness expected of the fairer sex in upper-class society. But even she never thought that she would become a social pariah, an outcast fending for herself on the mean streets of London. When the city is struck by a trio of unexpected deaths and suspicion falls on her sister and her father, Charlotte is desperate to find the true culprits and clear the family name.

World-renowned adventuress Beryl Helliwell cited for "reckless" motoring? Why, the very idea! Constable Gibbs just has it in for her. The solution? Charm the magistrate, of course. But days after Beryl's appearance before the bench, she and Edwina pay a visit to the magistrate only to find his home ransacked and the man himself lying dead at the bottom of a grand staircase. Given the state of the house, his death appears to be connected to a rash of robberies in the village.

The Earl of Wrexford possesses a brilliant scientific mind, but boredom and pride lead him to reckless behavior. He does not suffer fools gladly. So when pompous, pious Reverend Josiah Holworthy publicly condemns him for debauchery, Wrexford unsheathes his rapier-sharp wit and strikes back. As their war of words escalates, London's most popular satirical cartoonist, A. J. Quill, skewers them both.

Fresh from a six-month sojourn in Italy, Lady Julia returns home to Sussex to find her father's estate crowded with family and friends: but dark deeds are afoot at the deconsecrated abbey, and a murderer roams the ancient cloisters.

Inspector Treadles, Charlotte Holmes’ friend and collaborator, has been found locked in a room with two dead men, both of whom worked with his wife at the great manufacturing enterprise she has recently inherited. Rumors fly. Had Inspector Treadles killed the men because they had opposed his wife’s initiatives at every turn? Had he killed in a fit of jealous rage because he suspected Mrs. Treadles of harboring deeper feelings for one of the men? To make matters worse, he refuses to speak on his own behalf, despite the overwhelming evidence against him. 

The story opens with the apparently accidental drowning of a sixth form student in the Norfolk countryside. As a matter of routine, or so it seems, the case passes across the desk of Detective Sergeant Smith, recently returned to work after an internal investigation into another case that has led to tensions between officers at Kings Lake police headquarters. As an ex-DCI, Smith could have retired by now, and it is clear that some of his superiors wish that he would do so.