Examining evidence from young Bethany Riley’s murder, Sun Hill officers are forced to conclude that her 10-year-old classmate Mason Kemble could be involved. DI Neil Manson and DCs Grace Dasari and Mickey Webb have the difficult task of quizzing Mason at home, and the boy’s parents, Ryan and Susie, are distraught.

When Neil determines that Mason was present at Bethany’s murder, he gently arrests Mason, who is put into a patrol car. As the car pulls into Sun Hill, officers watch as the young boy is brought into custody on suspicion of murder. Meanwhile, Pc Roger Valentine arrives at Bethany’s parents’ house to break the news that Mason has been arrested for her murder.

Back at Sun Hill, Mason is questioned by Mickey and Grace, who gets frustrated when Mason refuses to answer her questions and is disturbed by his behaviour. When Grace loses her cool, officers decide to bring in Mason’s father Ryan, who agrees to help police by talking to his son about the events surrounding Bethany’s death.

During an emotional conversation with his dad, Mason finally reveals what really happened to Bethany…