When the mysterious Jean More dies in the small plane she learned to fly just two weeks earlier, she leaves her paramour David Lum with seemingly unanswerable questions: How had she come by the scars on her body? Why was she wanted by the FBI? What was the hidden purpose of her final flight? The puzzle of Jean's past leads David overseas to Paris, where he finds Jean's long-lost daughter and discovers the horror that connects Jean to a nuclear power plant. David's own life ultimately becomes forfeit as he finds himself adopting Jean's secret mission as his own.