This is the first in a series of mysteries set in London after World War I. I am not a fan of recurring detectives because characterization in these books is minimal, and the plots usually fairly predictable. Here, too, I found the mystery element only so-so, but the atmosphere is so finely wrought the book is well worth reading. Maisie becomes a maid for Lady Rowan Compton after her mother dies. Lady Compton gets her a tutor, Maurice Blanche, a man who is also an investigator, when she discovers Maisie is smart. A good student, she earns a spot at university. Alas, war breaks out. Maisie volunteers as a nurse at the front where she meets an officer and falls in love. After the war, she apprentices with Blanche, eventually opening her own detective agency. Her first case involves The Retreat, a suspicious home for disfigured war veterans. Lady Compton’s own son signed over his fortune to them. With the help of a war veteran in her office, Maisie solves the mystery and resolves her war-time love affair.