Plot Summary:Argolos, a war-ravaged and radiation-poisoned planet, has survived by becoming both an indoor recreation resort and a focal point for interplanetary understanding. However, bookings are down, and someone has recently sabotaged the tachyon generator that produces the main recreational activities, causing a horrific death to one of the tourists. With no identity cards on them, the Doctor and Romana fall under suspicion, but there's a third intruder whom no one's yet discovered.
Finding out-of-season Brighton beach somewhat lacking, the Doctor and Romana travel to the leisure planet Argolis - but there strange experiments are taking place.