Detective Lauren Pengelly investigates a woman’s bones found behind a derelict cottage in Penzance, which turn out to be twenty years old. On the same day, a girl called Isla is kidnapped from her nursery, prompting questions about a possible link between the two cases. Lauren and her second-in-command, Detective Matt Price, explore potential connections, including Isla’s estranged father’s odd behavior. Their investigation gains urgency when another girl is abducted, leading to fears the kidnapper may not have any intentions of stopping.