Insp. Monroe is skeptical but cautious when a young woman, Emma Crawford, rings Sun Hill and says she thinks her boyfriend may have hidden a bomb in the station. At Emma's flat, Ackland and Stamp find bomb-making equipment and a faxed warning due to be sent on a timer. PC Carver discovers a suspiscious paint can hidden in the ceiling - enough to trigger the evacuation of the station and the calling in of the Bomb Squad. The suspect, Ben Wallace, has been in trouble with the police before, and he is apprehended by DCI Meadows when he returns to the flat. As the Squad begin defusing the bomb, Ackland and Stamp visit Ben's parents whom he despises. The bomb is dismantled and the station declared safe, but Ackland and Stamp watch in horror as Ben's father is killed by a car bomb planted by his son.