This week's episode takes us back to 1986 and to the once industrious town of Greenock in the Central Lowlands of Scotland.

Elaine Doyle was 16 years old when she left home for a night out and never returned. Her naked body was discovered at 7am the next morning. It would take police 28 years to bring her killer to justice, but finally, in 2014, thanks to advances in DNA science, they got justice for Elaine.