Hollis spots a gang of youths hanging around a phonebox acting suspiciously. When he goes to investigate, the phone box explodes as the result of a volatile homemade bomb being planted inside. When a second bomb goes off at a nearby primary school, badly injuring a young boy, Brownlow and Hollis question the ringleader who reveals that there are a total of ten bombs, which he has sold to his friends or classmates. Brownlow then demands Monroe set up a widescale operation to search for the remainder of the bombs. When one is found inside a boiler cupboard of a young boy living in a council block, Conway has trouble evacuating an agoraphobic resident. When Hollis finally catches up with the culprit, he reveals he has one more bomb.