When Rendell Locke is brutally murdered by a boy, his three children and wife return to their father’s family home, the Key House. The mansion is located in the town of Matheson, near a high cliff complete with a cave. The youngest of the children, Bode, here hears the whispers of mysterious keys capable of activating various magical phenomena but, since initially no one pays too much attention to him, he ends up giving rope to a mysterious voice that comes from the bottom of a well. He says he is an Echo and is an extremely insidious entity who knows the secrets and powers of all the keys. His only limit: he cannot force the Locke to get the keys and so begins an intricate game of manipulation and threats.