Harman and Best arrive at the scene of a brutal assault, and whilst dealing with the victim, an abandoned baby is dumped in the back of their panda car. While the pair try to ID the victim, Harman receives a call from an anxious woman who wants to meet her to talk about the baby. Meanwhile, a man turns up at the station claiming to be the baby's uncle, and Kane decides to take him on the obbo to identify his sister, unaware that the man is actually the woman's husband and is responsible for the brutal attack on the woman's lover - the baby's real father. Meanwhile, Nixon investigates a brutal assault on a gym receptionist, only to find the woman's sister dead in the bath following a routine search of the victim's flat.