Just before Christmas Maisie and her employee, Billie see a man commit suicide in the street. The man was clearly a War Veteran and events very quickly turn Maisie back to her nursing days during the Great War. Soon after an anonymous letter is received by the police threatening violence if the comments in the letter are not adhered to.
Soon, Maisie is seconded to the Police as she and the police try and unravel the circumstances of the two issues. Is that deceased man part of the conspiracy to cause chaos in London? Next some animals in an animal shelter are found dead, the potential result of inhaling a poisonous gas, and then on the back of another letter some birds are found dead.
Maisie springs into action as she and Billy try to discover the truth whilst confronting their own fears. Billy meanwhile, is still struggling with his wife Doreen who can not move past her grief following the death of their little girl and soon Doreen is admitted to hospital to receive treatment.
In this book, which I think is the best, the author has tackled some real issues for the early 1930s. There has clearly been research done into early offerings by the War Office and poisonous gases and the 1930s treatment of those who were suffering from some kind of mental illness.