The Sign of Four Spirits

In "The Dark Side of the Bookshop," Gemma Doyle, owner of the Sherlock Holmes Bookshop, reluctantly attends a psychic fair in West London at the insistence of her friend Donald. After being barred from a séance, she overhears a chilling event that leads to a mysterious death, trapping her in a web of suspicion. With the room locked and the doors guarded, Gemma must unravel whether the danger comes from a living adversary or the supernatural forces invoked by the medium. The hunt for the killer begins as Gemma navigates treacherous clues and eerie revelations.