Newly retired detective Nevis 'Neil' Armstrong ponders the inscription on his leaving present, a gold watch. 'Nevis Armstrong - CID's finest'. But Neil wonders. Were there mistakes along the way?
'What's done is done,' argues his former boss. At university, Neil studied Theoretical Physics, maintaining his interest ever since. The watch, ticking away time, makes him think. Perhaps there is a way to right past wrongs. What if what's done is not done after all?
Twenty-five years earlier. 1977. Britain is suffering with one million unemployed and rampant inflation. Industrial unrest and racial tensions spark violence. Punk rock is the voice of a disaffected younger generation.
In South London, Neil, recently promoted to Detective Inspector, is spending an off-duty evening in his local with a bottle of wine, the latest New Scientist magazine and the jukebox, when a young woman disturbs him. Vienna, forthright and named after a song Neil doesn't know, is different from the pub's regulars, with her blue-streaked hair, nose stud and dolphin tattoo.
Who is Vienna? Why is she in The White Horse? And how does she know that Neil will shortly be called to Clapham, where an anti-fascist protester lies dead after a National Front march?