In our first case, father of four, Pat McCormick, goes missing in Comber, Northern Ireland, leaving his family desperate for answers. Police suspected he'd come to harm but struggled to find proof without a body. Then, six weeks after his disappearance, they made a shocking discovery - the man's body was found stuffed in a wheelie bin and dumped in a lake. They soon had two prime suspects, but detectives needed to find a way to place them and the victim at the same place at the same time. They enlisted the help of Paul Hope, a cell site expert, who by analysing their mobile phone network data was able to track their movements on the night of the murder and help prove their guilt. With emotional testimony from Pat's daughter Morgan, who still misses her beloved father. Traces of soil are often used to answer the "where" questions in an investigation. Where something happened? Where something went? Where an investigation might lead? In our second case, which took place in Scotland, 63-year-old grandfather Tony Parsons was on a charity cycle ride but seemed to vanish into thin air. His disappearance became a major missing person's inquiry, but with no clues as to his whereabouts, his body wasn't found. When police get a major tip-off three years later, they turn to soil expert Professor Lorna Dawson to help unearth the truth about what really happened to him and lead them to the suspects. With fascinating evidence about the case from crown prosecutor Alex Prentice.