Gerard Roylake returns from Germany on the death of his father to take up his inheritance at Trimley Deen. On his first evening he walks to the nearby River Loke, "the ugliest, muddiest stream in England" which runs back of an old mill, inhabited by the miller and recognises his childhood friend, Cristel Toller, the miller's beautiful daughter. He also meets a deaf man living at the mill known only as The Lodger... romantic jealousy, attempted murder and the disappearance of Cristel ensues.