The dawn of 1921 finds Mary Russell, Sherlock Holmes's brilliant young apprentice, about to come into a considerable inheritance. Nevertheless, she still enjoys her nighttime prowls in disguise through London's grimy streets, where one night she encounters an old friend, now a charity worker among the poor. Veronica Beaconsfield introduces Russell to the New Temple of God, a curious amalgam of church and feminist movement, led by the enigmatic, electrifying Margery Childe. Part suffragette, part mystic, she lives quite well for a woman of God from supposedly humble origins. Despite herself, Russell is drawn ever deeper into Childe's circle. When Veronica has a near-fatal accident -- and turns out to be the fourth bluestocking in the group to meet with misadventure after changing her will -- Russell and Holmes launch a quiet investigation. But the Temple may bring the newly rich Russell far closer to heaven than she would like....