In Hull, a vulnerable man is violently attacked in his own home and left for dead after his assailant sets fire to his flat. Emergency services rush to the scene, and firefighters pull the 54-year-old man from the inferno. The victim is in a critical condition and shows obvious signs of assault. With his life hanging in the balance, the case is escalated to Humberside Major Crime's Team. CCTV identifies a suspect arriving at the crime scene and leaving just before a passerby spots flames and smoke billowing from the same flat. During the ensuing search for the suspect, investigators uncover an audio recording where a voice, believed to be the attacker, taunts, 'enjoy the fire'. But who is the perpetrator, where is he, and what drove him to kill?