In the early 19th century, Blair Harvey comes to Exeter with a degree from Oxford, and high hopes of forging a career in the legal profession. But a brush at Exeter Fair with an Irish prostitute pricks his conscience, and he seeks spiritual refuge with Dr. Percy Brougham, a high Church Anglican who is flirting with Roman Catholicism. Blair sets his sights on Brougham's independently minded daughter Susannah. They marry, and when Brougham dies of apoplexy, Blair inherits the family fortune. He sets up a thriving shipping business in Teignmouth, and for a while assumes the role of a paterfamilias and patron of the arts. But when he witnesses the wreck of a ship off the Devon coast and is begged to lead the local people in prayer for the shipwrecked sailors, he is conscience-stricken, and undergoes an extraordinary conversion to Christianity. Obedient to the precepts of the Plymouth Brethren, Blair sells house and home in order to set himself up as the leader of a little community of Believers on the edge of Dartmoor, where he embraces a life of hardship and poverty. But as the years pass, Blair's rigid adherence to the exclusivist teachings of the Plymouth Brethren destroys his family, his prosperity and his peace of mind, and turns him into a figure of grotesque tragedy.