When DCI Jim Edwards takes on the homicide investigation of a murdered policewoman, he has no idea how it is going to impact on his relationship with his family. When it transpires that his deaf niece, Amelia, witnessed the murder it puts huge pressure on Jim; he decides to withhold Amelia as a formal witness to protect her, but Jim struggles to make headway with the case whilst keeping Amelia's identity a secret.

Amelia identifies one of Jane Shilliday's killers, a detective on the Drugs Squad. When Jim learns that Rocky and Shilliday were romantically involved, he is certain that the large scale corruption on the Drugs Squad was the motive for Jane Shilliday's murder, but he can't prove it. When Amelia's implant is returned to her via her audiologist, she realises, with horror, that Shilliday's killers know who she is.

Amelia and Jim's families are subjected to intimidation tactics by the corrupt Drugs Squad in an attempt to thwart the investigation into Jane Shilliday's murder. When Amelia lip reads a conversation between Rocky and Mac and relays the information to Jim, he becomes certain that Mac is Jane Shilliday's other killer. When Lee Griggson comes to Amelia's house to intimidate her, she runs away, without taking her cochlear implant.

Amelia heads to a rural police station but refuses to reveal her identity, worried that the corrupt officers on the Drugs Squad might be able to track her down. Amelia makes contact with Jim, who races to collect her. Jim realises too late that Mac and Lee have followed him. Jim confronts them, insisting Amelia head home for her own safety, but Amelia tracks down Rocky at the boxing gym and takes matters into her own hands.