Crown Prosecutor Helen West, her less-than-clean garden flat and her relationship with senior Geoffrey Bailey are all in need of a little care and attention. Further up the no. 59 bus route but a world away lives Cath, the 'treasure' who begins cleaning for Helen. At first the latter is only too happy to turn a blind eye to the tragedy of Cath's life but then the long arm of coincidence clutches at them all. Bailey is caught up in a seemingly open and shut case involving the death of Cath's much-loved brother - yet something is making him uneasy. Then Helen becomes a witness to the destructive forces of love and guilt and finds herself applying her own version of justice.