The Galactic Federation is at war with the rapacious Sorson Empire, and losing. Two Federation ambassadors, negotiating a peace treaty, have been kidnapped by the Sorsons. One, however, has escaped, and joined forces with the anti-Sorson rebellion on the planet Desh. From there, he heads back home, to Earth, and his friends John and Tim of the Tomorrow People, pursued by the vengeful Sorsons.