Teenage super-sleuth Enola Holmes is back at it again! After a mysterious group of anarchists abduct her brother Mycroft, Enola investigates his disappearance in hopes of rescuing him and recovering something he took from her. With the help of Lord Tewkesbury and a boy from the streets named Shag, she unravels a web of mystery that takes her deep into the London underground as she races to save the day!