Webb and Spears investigate when a house fire traps two young girls, who end up in hospital in a critical condition. Meadows is later assigned to lead the investigation when suspicion soon falls on a loan shark who was seen outside the house just before the fire. When witnesses place him elsewhere at the time of the fire, suspicion then falls on the girls' father, however questioning him is delayed when one of his daughters succumbs to her injuries. With Webb convinced of his guilt, Spears clashes with him when she suspects the mother is to blame. After cracking the case, Webb and Spears grow closer.

Boyden spearheads a raid on a brothel, which uncovers several illegal immigrants from Croatia being forced to work as prostitutes. The owner of the premises, Carson, agrees to reveal who is bringing the girls into England in exchange for a lesser charge. However, on the way to court, the police van is ambushed and Carson is kidnapped. After the car used in the ambush is found with blood stained seats, it is suspected Carson has been killed. Carson's lawyer, Doyle, eventually agrees to set up a meeting with Luca, and Boyden sets up a surveillance operation on a locker. Meanwhile, McCann agonises as he waits for word on a transfer that hinges on the result of his Sergeant's exams.