Lie By Moonlight. Number 4 in series

During an investigation into a woman's death, gentleman thief turned private inquiry agent Ambrose Wells finds himself at Aldwick Castle - and in the middle of chaos. The building is in flames. Men are dead. And a woman and four young girls are fleeing on horseback. A confirmed loner, Ambrose nevertheless finds himself taking Miss Concordia Glade and her young charges under his wing. With their lives at risk, he insists they must remain in hiding until he is able to unravel the truth behind their recent imprisonment at the castle.
Concordia has never met anyone like Ambrose Wells before. He is bold, clever, and inscrutable - even to the perceptive gaze of a professional teacher such as herself. He is also her only hope to protect her pupils from the unscrupulous men who are after them - powerful, shadowy figures who will stop at nothing to get what they want.