As India celebrates the arrival of a momentous new decade, Inspector Persis Wadia stands vigil in the basement of Malabar House, home to the city's most unwanted unit of police officers. Six months after joining the force she remains India's first female police detective, mistrusted, sidelined and now consigned to the midnight shift. And so, when the phone rings to report the murder of prominent English diplomat Sir James Herriot, the country's most sensational case falls into her lap.

England, 1920. Eleanor Swift has spent the last few years travelling the world: taking tea in China, tasting alligators in Peru, escaping bandits in Persia and she has just arrived in England after a chaotic 45-day flight from South Africa. Chipstone is about the sleepiest town you could have the misfortune to meet. But then, from the edge of a quarry, through the driving rain, Eleanor is shocked to see a man shot and killed in the distance. Before she can climb down to the spot, the villain is gone and the body has vanished.

Only she knows the truth. Only he can tell the world. Vienna, 1946. A brilliant German scientist spirited out of the ruins Nazi Europe in search of a new life. Moscow, 1964. A rising star of the British diplomatic service whose job is not what it seems. London, the present day. A once promising academic offered an opportunity to seal his place in history. Their stories, their lives, and the fate of the world, are bound by a single document: The Scarlet Papers. The devastating secrets contained within teased by a brief invitation: Tomorrow 11AM. Take a cab and pay in cash. Tell no one.

In 1892, Bombay is the center of British India. Nearby, Captain Jim Agnihotri lays in Poona military hospital recovering from a skirmish on the wild Northern frontier, with little to read but newspapers. The case that catches Jim's attention is being called the crime of the century: Two women fell from the busy university’s clock tower in broad daylight. Moved by the widower of one of the victims - his certainty that his wife and sister did not commit suicide - Jim approaches the Framjis and is hired by the Parsee family to investigate what happened that terrible afternoon.

Umiko Wada has had enough excitement in life. With an overbearing mother and her husband recently murdered, she just wants to keep her head down. As a secretary to a private detective, her life is pleasantly filled with coffee runs and paperwork. That is, until her boss takes on a new case. A case that is surrounded by shadows. A case that means Wada will have to leave Tokyo and travel to London.