In the twenty-second century Earth obtains limitless, free energy from a source science little understands: an exchange between Earth and a parallel universe, using a process devised by the aliens. But even free energy has a price. The transference process itself will eventually lead to the destruction of Earth´s Sun - and of Earth itself.
Only a few know the terrifying truth - an outcast Earth scientist, a rebellious alien inhabitant of a dying planet, a lunar-born human intuitionist who senses the imminent annihiliation of the Sun. They know the truth - but who will listen? They have foreseen the cost of abundant energy - but who will believe? These few beings, human and alien, hold the key to the Earth´s survival.
AUTHOR: Isaac Asimov