The first of an exciting new series of nostalgic crime sagas, steeped in historical detail with engaging characters and an old-fashioned murder-mystery at its heart. Set against the backdrop of WW1, Mayfair 100 is the telephone number for a small specially-formed crime-busting team based in a house in Belgravia.

London, 1915. Just 10 months into the First World War, London is flooded with women taking over the work vacated by men in the Armed Services. Chief Inspector Peter Beech, a young man invalided out of the war in one of the first battles, is faced with investigating the murder of an aristocrat and the man's wife, a key witness and suspect, will only speak to a woman about the unpleasant details of the case. After persuading the Chief Commissioner to allow him to set up a clandestine team to deal with such situations, Beech puts together a small motley crew of well-educated women and professional policemen.

As Beech, Victoria, Caroline, Rigsby and Tollman investigate the murder, they delve into the seedier parts of WWI London, which takes them from the criminal gangs to the brothels and the underground drug rings supplying heroin to the upper classes. Will the Mayfair 100 team solve the murder? And if they do, will they be allowed to continue working as a team?