A young woman is found dead in her bedroom surrounded by rose petals - the latest victim of 'The Lover'. Struggling under the weight of an internal investigation, DI Dominic Bell is no closer to discovering the identity of the killer and time is running out. As the murders escalate, Clementine Starke joins an online true crime group determined to take justice in their own hands - to catch the killer before the police. Hiding a dark secret, she takes greater risks to find new evidence and infiltrate the group. As Starke and Bell get closer to cracking the case neither of them realise they're being watched. The killer is closer to them than they think, and he has his next victim - Clementine - firmly in his sights.