19th century London. Ever since the Great Stench, which occurred two years earlier, London has been plunged into darkness by a perpetual fog. More troubling yet, some of the dead are coming back to life. They call them the Putrefied. Léandre, a young lord and medical student, is convinced these creatures hold the key to saving his sister, who suffers from an incurable disease. But to unravel the mystery, he’ll need to team up with Winifred, a journalist who’s as unbearable as she is intelligent.