The UK’s biggest and most successful true crime documentary series continues its new run, featuring unprecedented access behind the scenes of police investigations into major crimes. On a quiet Sunday in a suburb in Cambridgeshire, a man drops his son at the doorstep of his ex-partner’s home. Inside, the ex-partner’s new partner is cooking Sunday dinner. Within minutes, one of the men is lying bleeding to death on the doorstep and the other man has fled the scene. Paramedics race to the scene, but the injured man is pronounced dead from multiple stab wounds. As officers scramble, a manhunt is launched for a murderer. CCTV reveals that the suspect escaped to London after a visit to his parents. Detectives from Cambridgeshire’s Major Crime Unit decide to arrest the parents of the missing man and hope that they will give away where he is hiding and reveal what lay behind the attack. Cameras follow each twist and turn of the operation as police grapple with the hunt to find the missing killer and officers push to see how far family loyalties can be stretched before they break. This is real-life drama in which the clash between the pursuit of justice and the strength of blood ties is brutally exposed. A story where what is revealed as fact is more compelling than fiction.