Take a clever sci-fi idea; everyone gets genetically fixed to stop ageing at 25 (yay). They also get a fixed such that basically every second they live beyond that costs money, and if they run out of money on their wrist bank, they die (boo). If you like to think science-fictional thoughts, you probably think of some interesting ideas about that. All I can say is, maybe you should have written it, because all this really is, is a series of against the clock chase scenes with really high stakes.