Living on her family's idyllic lakeside estate in Cornwall, England, Alice Edevane is a bright, inquisitive and precociously talented 16-year-old who loves to write stories.

One midsummer's eve, after a beautiful party drawing hundreds of guests to the estate has ended, the Edevanes discover that their youngest child, 11-month-old Theo, has vanished without a trace. He is never found, and the family is torn apart and the house abandoned.

Decades later, Alice is living in London, having enjoyed a long successful career as a novelist. Miles away, Sadie Sparrow, a young detective in the London police force, is staying at her grandfather's house in Cornwall. While out walking one day, she stumbles upon the old Edevane estate - now crumbling and covered with vines. Her curiosity is sparked, setting off a series of events that will bring her and Alice together and reveal shocking truths about a past long gone...yet more present than ever.