Susannah is in a dark place, grieving the loss of her daughter, when she's caught off guard by a visit from a mysterious new client called Jon. While in a trance, Jon makes a shock confession, compelling Susannah to embark on a deadly mission.

Susannah is shocked when her former lover, Richard Groves, doesn't take her concerns about Jon's murders seriously and she soon realises that he's hiding something. She then locks horns with Richard and his wife, Natasha, and manages to get a lead.

Susannah gets her ex-client, officer Louisa, to open up about a witness who saw a man matching Jon's description killing her friend. When Louisa admits she was threatened into silence, Susannah realises they both could be in danger.

Susannah goes to the secure psychiatric hospital where her ex-husband, Danny, is being detained. However, she is shocked to discover that he's no longer there and suspects that Dr Alistair Underwood is covering up the incident.

Susannah finally manages to track down Sapphire, the witness who Louisa met with. Susannah is then shocked to learn some truths about her daughter's death and soon realises that Sapphire is the next target.

Susannah is convinced that she's in danger, so she asks her ex-client, Joseph, for help. Things become increasingly desperate as Susannah realises that both she and Joseph, alongside Sapphire, are now targets.