London, April 1882. When cool-headed Phyllida visits the World's End Investigation Bureau to offer a curious case concerning her fiancé, proprietor Lily Raynor is intrigued - and privately excited. Phyllida's fiancé, Wilberforce, is currently in an asylum in Brittany, after a tragic incident which resulted in the death of his father. Did he kill him on purpose - or was it an accident? Wilberforce's innocence looks increasingly in doubt when another murder happens at the asylum - and the evidence points to Wilberforce being the culprit. With the engagement hanging in the balance, Phyllida wants to know the truth before it's too late. Lily and her assistant, Felix Wilbraham, journey to rural France to uncover the truth, but the case takes an unexpected turn when they discover that the accused man has escaped the asylum. Soon the intrepid investigators are in over their heads. . .