Valentine investigates a road traffic accident involving an eight-year-old boy, and is devastated to have to inform the father when the boy subsequently dies of his injuries. Although having been at the wheel of a stolen car, forensics confirms that the driver was not above the speed limit and was driving safely – news which the young boy's father doesn't take too well. Meanwhile, with 50 years of Sun Hill looming on the horizon, Hollis is putting into place last minute preparations for a celebratory due, including inviting a guest speaker, former DCS Charles Barnet, to compere the night. However, whilst out on patrol with Stamp and Powell, Barnet suffers an injury whilst making an arrest. (thetvdb.com)