What starts out as a simple, reckless mid-life affair between a genetic scientist named Yvonne and a Westminster paper pusher takes an intriguing turn when she realizes he’s a spook – then suddenly gets very dark indeed. A provocative study of obsession, longing and just how far down a criminal path desire can take you.
Dr Yvonne Carmichael seems to have it all - a respected career, a beautiful home and family. However, nothing is ever as it appears, and when she receives an unexpected proposition from an enigmatic stranger, Yvonne is shocked by the passion he awakens in her. But gradually she begins to realise that there is much more to her lover than meets the eye, and she could be playing a very dangerous game indeed.
In the aftermath of what has happened, a devastated Yvonne shuts down. She feels unable to talk to the police or her husband, but as a campaign of terror is mounted against her, she is pushed to her limits and turns to her former lover, Costley, for advice. They meet for one last time and share a passionate afternoon together, before Costley takes control of the situation and Yvonne is plunged from one nightmare into another.
Yvonne's life is turned upside down yet again, when she is ripped away from her family and arrested for murder. In shock, Yvonne denies everything, but the police are convinced that she and Costley colluded in cold blood. Their trial begins and very quickly Yvonne realises that everything she thought she knew about her lover was a lie. And right now he's all that's standing between her and a prison sentence.
The murder trial continues, with Costley's lawyer Bonnard basing her defence on evidence that Costley suffers from a personality disorder which would have impeded his ability to react normally during an altercation with Selway. The prosecution attack this claim. When Yvonne finally takes to the stand, she sticks firmly to her story and confidently holds her own.