It is winter 1863, and Richard Shenstone, aged seventeen, has been sent down — "rusticated" — from Cambridge under a cloud of suspicion. Addicted to opium and tormented by sexual desire, he finds temporary refuge in a dilapidated old mansion on the southern English coast inhabited by his newly impoverished mother and his sister, Effie. Soon, graphic and threatening letters begin to circulate among his neighbors, and Richard finds himself the leading suspect in a series of crimes and misdemeanors ranging from vivisection to murder.