11 - Door with Seven Locks by Edgar Wallace

In his final day at Scotland Yard, Dick Martin stumbles upon an enigmatic mystery that refuses to let him retire in peace. A missing heir, a stolen library book, horrifying vivisection, and a string of chilling murders are all tied to a cryptic tomb with seven intricate locks. The keys, scattered and hidden, are the only route to unmask a malevolent plot aiming at a colossal fortune. As Martin delves into the conundrum, seemingly random occurrences start to form a frightening pattern. Will he untangle this deadly web before his retirement day ends?