England, 1911. The Reverend Albert Canning, a vicar with a passion for spiritualism, leads a happy existence with his naive wife Hester in a sleepy Berkshire village. As summer dawns, their quiet lives are changed for ever by two new arrivals. First comes Cat, the new maid: a free-spirited and disaffected young woman sent down from London after entanglements with the law. Cat quickly finds a place for herself in the secret underbelly of local society as she plots her escape. Then comes Robin Durrant, a leading expert in the occult, enticed by tales of elemental beings in the water meadows nearby. A young man of magnetic charm and beauty, Robin soon becomes an object of fascination and desire. During a long spell of oppressive summer heat, the rectory at Cold Ash Holt becomes charged with ambition, love and jealousy; a mixture of emotions so powerful that it leads, ultimately, to murder.

England, 1937. In the village of Blacknowle on the Dorset coast, fourteen-year-old Mitzy Hatcher has endured a wild and lonely upbringing. Shunned by her neighbours, the arrival of renowned artist Charles Aubrey, along with his exotic mistress and their daughters, is like a breath of fresh air. As Charles's muse, Mitzy develops a deep and abiding bond with the Aubrey household over the course of the following three summers. Gradually, Mitzy begins to perceive a future she had never thought possible, and a powerful love is kindled in her. A love that will grow as she does: from innocence to obsession; from childish infatuation to something far more complex. It will be almost seventy-five years before the consequences of this potent desire are fully played out, as a young man in an art gallery looks at a hastily-drawn portrait and wonders at the intensity of it. The questions he asks will lead him back to Blacknowle, and draw him to the truth about those fevered summers in the 1930s...