On a beautiful summer evening in the quiet town of Marlow, a young woman is walking home from church. She passes a man who is looking at the engine of his car. He turns round, smiles at her and throws acid into her face. Then her father, the scientist George Ashton, disappears. And her sister, Penny, discovers that her husband-to-be, Malcolm, is a government agent. Why has Ashton disappeared, and why is Malcolm told to hunt for him? Who is George Ashton, anyway? And who is the enemy?