"Two days ago, I was an unemployed nurse. Now I’ve found out London is populated by hidden monsters."Hannah Chadwick used to save human lives—until she blew the whistle on corporate malpractice and found herself barred from working at every hospital in the city. Broke and desperate, she accepts a job at a nondescript surgery hidden in a London side street. Her employer, the eccentric Julius Wayworthy, treats patients with "curious physiologies."But these conditions aren’t just rare. They’re impossible.Deep beneath the streets, fueled by a magical energy called linether pulsing through the tunnels of the London Underground, exist the LineFolk. This secret society of elegant haemovores and brutal shapeshifters has survived for centuries by hiding in plain sight. They are bound by one absolute law to maintain their human disguises: Stay on the lines.When Hannah’s colleague, Axton Flynn, undergoes a bone-snapping transformation into a seven-foot feline to save her from a mugging, the veil is torn. Hannah realizes she is the only human working in a hidden world of monsters. And in the Underground, witnesses have a very short shelf life.With a rogue transport detective circling the surgery and a shadowy killer stalking the tunnels, Hannah must uncover why Wayworthy really hired her. Because her predecessor didn't just disappear.She was hunted.Welcome to a London you were never meant to see. This British urban fantasy is fast-paced, atmospheric, and perfect for fans of Rivers of London and Neverwhere.Welcome to the Underground. Just don’t stray from the lines.