Kemlo and Krillie, together with Krillie's sister Krinsetta, set out for a visit to S Belt in Kemlo's space scooter. They are attacked by three boys from S Belt, who kidnap Krinsetta. Kemlo gives chase, and both his and the other craft are forced down, off course, on to the Zones of Silence, part of a large area known as the Dead World where the slightest whisper is magnified into a roar...

The inhabitants of the Zones have no audible form of speech, but use instead a highly developed system of thought transference. These creatures are friendly, but too friendly: they attempt to drug the minds of visitors with thought impulses compelling them to stay on the Zones. Kemlo is able to resist this powerful impulse, but...