An advanced race of aliens descends upon Earth with a single goal - the blood of eight million humans to save their own dying planet. The aliens have planted a doomsday device over the North Pole, and if the Earth doesn't supply enough victims, they'll activate it and destroy the planet. However, if the Earth does comply, the device will become a power supply capable of meeting all of its needs for the next 300 years. Every country in the world must surrender some citizens, and the United States begins a lottery system. Anyone unlucky enough to be chosen is dead within 24 hours, rendered into liquid, which is then sent back to the alien world. One scientist, Steven Chase, whose daughter is chosen for the lottery, decides to fight rather than surrender his only child. Suddenly he must race against time to find the aliens' weakness as the invaders decide to abandon their agreement and simply harvest humans at will, leaving death and destruction in their wake.