Consumption has ravaged Louise Pinecroft's family, leaving her and her father alone and heartbroken.
But Dr Pinecroft has plans for a revolutionary experiment: convinced that sea air will prove to be the cure his wife and children needed, he arranges to house a group of prisoners suffering from the same disease in the cliffs beneath his new Cornish home.
Forty years later, Hester Why arrives at Morvoren House to take up a position as nurse to the now partially paralysed and almost entirely mute Miss Pinecroft. Hester has fled to Cornwall to try and escape her past, but she soon discovers that her new home may be just as dangerous as her last.