In 1863 London, a photographer is murdered, his body found at the Royal Academy Exhibition shortly after his assistant, Bridget, is locked in the dark-room at the studio. Then art expert Giovanni Morelli is attacked. With the police unable to see the connection, illustrator Jo Harris must help Bridget uncover the clues among wealthy art collectors and purveyors of photographic pornography, with help from the likes of Dante Gabriel Rossetti and Sir Charles Eastlake.