The morning after the explosions that rocked London, shocked Sun Hill officers struggle to deal with the sudden death of their colleague, Pc Emma Keane. The bombers are still at large, and as the officers wait to be briefed they are introduced to DI Karen Lacy from the Counter Terrorism Unit who will be leading the investigation. As Stone and Sally work together to track down main suspect, Carl Adams, Stone begins to reveal how guilty he feels about it. At that moment, they spot Carl trying to escape on a motorbike and give chase. But after Sally arrests Carl, her emotions take over and she falls into Stone's arms, sobbing. Back at Sun Hill, Carl admits that bomb components have been sent to his house, but swears he had no idea who they came from. But as DC Mickey Webb and Trainee DC Kezia Walker search Carl's house, Kezia triggers the switch to a bomb and is unable to move from the spot. Meanwhile, Sergeant Smith talks to Stone whose pent up emotions take over. Consumed with rage and guilt over Emma's death, Stone grabs Smithy by his collar and Inspector Gina Gold is forced to pull the two sergeants apart.
