Caroline Foster arrives in Whitechapel searching for her missing brother, Charlie, as Jack the Ripper terrorises Victorian London. With little money and nowhere to stay, she becomes the maid at the Whitechapel Full Moon Society, where Charlie once lived. Its secretive residents offer shelter but impose unsettling rules: avoid the barred room and hide throughout every full moon. Caroline’s concern deepens when she learns that the previous maid was murdered and that new victims share connections to the Society. Refusing to abandon Charlie, she investigates the house despite mounting danger and suspicion. Her search reveals that the Society’s secrets extend beyond the Ripper murders into curses and ancient folklore. To find her brother and survive, Caroline must decide whom she can trust and confront a hidden world far stranger than the monster stalking London’s streets.