The Comfort of Ghosts by Jacqueline Winspear

 The author says this is the last of the Maisie Dobbs books. The series started with Maisie a battlefield nurse during WWI and ended after WW II. Maisie finds four early teenage kids squatting at Lord Julian's London house. They tell her they witnessed a murder and are afraid the cops are after them. She also finds a badly injured soldier, who turns out to be someone she knows. While trying to find a safe place to stash the kids and the soldier--and figure what really happened with the murder they claim to have witnessed-- Maisie comes across a pile of letters that turn out to be related to 2 people from her past--which sends her off in search of someone who may be part of her extended family. It's a good wrap-up to the series, though it's sad not to have any more Maisie adventures to look forward to.