While investigating a double murder in Surrey, Brock and Poole discover that the dead couple were involved in a financial crime with international implications.

It is New Year's Eve 1915 and the Hardcastle family are welcoming 1916 at their home in Kennington, London. But an hour into the New Year, Hardcastle is called to a murder in a jeweller's shop in Vauxhall. In a first for the A Division senior detective, the killers apparently made their escape in a motor car.