A terrorist is about to blow up an airliner. As he prepares to carry out his murderous scheme, the villain's gaze is shifty and his heart is racing. And, just before disaster, a special police force swoops in to save the day.
No, it's not a scene from some potboiler novel or the movie Minority Report - although many people are making the comparison with that science fiction film, in which Tom Cruise solves crimes before they happen based on predictions about the future. Instead, it's a plan from the US Department of Homeland Security, one that might soon be coming to airports near you.
Perhaps the only good thing we can say about the Future Attribute Screening Technology (Fast) project is that it will not involve enslaved psychics suspended in a tub of goo, as in Minority Report. Homeland Security has dispensed with the mind-readers and instead relies on technology to "read" physiological signs of criminal intent.
Will these signs be confused with those of a nervous airline passenger? It seems rather likely. And we still want to know if the colour of someone's skin might be seen as an indicator of a terrorist threat.
"The premise of this approach - that there is an identifiable physiological signature uniquely associated with malicious intent - is mistaken," Steven Aftergood, a research analyst at the Federation of American Scientists, told the journal Nature. "The whole thing seems like a charade."
Unfortunately, every airline passenger might end up caught in the act.