Secret remains

When a group of young women working in London's sex trade become involved in a murder investigation, their fabricated account of events leads to the wrong suspect becoming convicted. Twenty years later, the innocent person is free - but somebody has started killing the women connected to the case. With the threat of blackmail hanging over them, the women have a lot to lose and nobody has a cast-iron alibi. In a case where nothing is quite what it seems, can Detective Inspector Paul Banham stop a cold-blooded killer?