The story begins in Paris 1742, when the body of a woman named Lia de Beaumont is found in a casket floating along the Seine.[6] The only clue regarding her death is the word "Psalms", which is written in blood on the lid of the casket. D'Eon de Beaumont, Lia's younger brother and a knight in service of King Louis XV, takes it upon himself to investigate his sister's mysterious death, along with the strange disappearances of a number of French women. In his journey he comes across three companions to help him.