It was around 7 pm on August 13, 1981, and 36-year-old Carol Morgan was working the till at her corner shop in a town called Leighton Buzzard in the county of Bedfordshire, England. 

On that night, Carol was working at the shop alone, getting ready for closing, which was at 6pm. But someone surprised her. She was later found in a pool of blood. 

Forensic testing revealed that Carol had been brutally beaten and stabbed with a weapon, something like an axe or a machete, something heavy but very sharp. She had been hit so hard that pieces of her skull and brain matter were on the floor. 

The police investigation would last 43 years and would take a lot of strange twists and turns to find out: Who came into that store and hacked Carole to death?