On a sunny afternoon in late June, Cambridge professor Joseph Reavley is summoned from a student cricket match to learn that his parents have died in an automobile crash. Joseph’s brother, Matthew, as officer in the Intelligence Service, reveals that their father had been en route to London to turn over to him a mysterious secret document—allegedly with the power to disgrace England forever and destroy the civilized world. A paper so damning that Joseph and Matthew dared mention it only to their restless younger sister. Now it has vanished.

His name, they tell him, is William Monk, and he is a London police detective. But the accident that felled him has left him with only half a life; his memory and his entire past have vanished. As he tries to hide the truth, Monk returns to work and is assigned to investigate the brutal murder of a Crimean War hero and man about town. Which makes Monk’s efforts doubly difficult, since he’s forgotten his professional skills along with everything else.

Spring, 1918. The Great War is at a crucial stage, the Germans are making one last push into France, and the Allies are struggling to hold them back. Battle lines are shifting, and men, and their machines, are being sent up and down the front to shore up defenses. Major Heathcliff Lennox, and his batman Greggs, are told to report to their new HQ. They set off on a sunlit day to fly the distance, but the enemy is never far away, and disaster strikes. They're sent crashing to the ground behind enemy lines, where life, death, and love await.

When a maid in the upper class Ellison household is strangled, Inspector Pitt is called in to investigate. He finds a world ruled by strict manners and social customs, where the inhabitants of the Ellison's neighborhood appear to be more outraged by the thought of scandal than they are by murder. Inspector Pitt finds a most unlikely ally in Charlotte, the Ellison's spirited daughter. But as the murders continue, Charlotte and Pitt find themselves drawn together by more than the investigation.

The year is 1861. The American Civil War has just begun, and London arms dealer Daniel Alberton is becoming a very wealthy man. His quiet dinner party seems remote indeed from the passions rending America. Yet investigator William Monk and his bride, Hester, sense growing tensions and barely concealed violence.

It's 1910, and Daniel Pitt is a reluctant lawyer who would prefer to follow in the footsteps of his detective father. When the biographer Russell Graves, who Daniel is helping defend, is sentenced to execution for the murder of his wife, Daniel's Pitt-family investigative instincts kick in, and he sets out to find the real killer. With only 21 days before Graves is to be executed, Daniel learns that Graves is writing a biography of Victor Narraway, the former head of Special Branch and a close friend of the Pitts. And the stories don't shed a positive light. Is it possible someone is framing Graves to keep him from writing the biography-maybe even someone Daniel knows in Special Branch? The only answer, it seems, lies in the dead woman's corpse.

Determined to find the men responsible for her disgraced father's murder, Lady Arianna Hadley disguises herself as a man and contrives to be hired as a chef in one of London's aristocratic households. But when the prince regent is poisoned by Arianna's special chocolate dessert, she finds her own quest has become intertwined with a far more deadly intrigue. The earl of Saybrook is asked by the government to investigate. When someone tries to kill them both, they become reluctant allies in the hunt to discover what evil is afoot.

London, 1861. Samantha Kingston has lived under the control of her overbearing uncle since the death of her parents six years ago. Trapped by the conventions of her gender and social class, she is desperate to find a way out. But when her aunt and uncle are murdered, the freedom she sought seems even further out of reach. A suspect in the crime, she finds herself on the run, unsure whom to trust, lost in the underworld she had only ever read about in the pages of a Dickens novel.

Tabitha, Lady Chesterton, the Countess of Pembroke, is newly widowed at only 22 years of age. With no son to inherit the title, it falls to a dashing, distant cousin of her husband's, Jeremy Chesterton, known as Wolf. It quickly becomes apparent that Wolf had consorted with some of London's most dangerous citizens before inheriting the title. Can he leave this world behind, or will shadowy figures from his past follow him into his new aristocratic life in Mayfair? And can Tabitha avoid being caught up in Wolf's dubious activities?

Hours later, the man’s cold body lies in the city mortuary, alongside the woman he couldn’t save. And his sister, unconventional nurse Gemma Tate, tracks down troubled police inspector Sebastian Bell to unravel the truth. Sebastian has enough pressure to solve the murder of an aristocratic heiress without Gemma meddling in his case. But the cryptic sentences she brings him from her brother’s notebook could be a crucial lead. If only they knew what “milky way” meant.