Nothing could disturb the serene peace of the planet Deva-Loka - or could it? An expeditionary force from Earth is dangerously out of control—and it's not only the peaceful race of the Kinda who are at risk... A gentle stroll in the lush jungle leads the Doctor and Adric to an unexpected confrontation-and puts them at the mercy of a maniac... But it is Tegan, lulled to sleep by mysterious wind-chimes, who comes the closest to the real danger that threatens not only her sanity but the existence of the whole planet...