Sally Magnusson presents a series that goes behind the scenes at police forces' Missing Persons Units across the UK and looks at baffling cases from the National Missing Persons Helpline. Following the death of her youngest daughter, Anne Simpson retired to Skegness with her partner, but disappeared after a weekend visit from her family in September 2004. Can Lancashire Police find the holidaymakers that Anne was drinking with before her disappearance? 71-year-old Brian Hartley was last seen on CCTV after going for a drink with friends in Preston town centre on 27th November 2006. What implications does the fitting of a pacemaker have on his disappearance?