"It's an ancient name. From the dark time..." It's been hundreds of years and several regenerations since the Doctor last visited the insect world of Vortis. Much has changed during his absence, but not necessarily for the better. This now green and pleasant land isn't the paradise it first appears. Something malevolent is living out in The Desolation... And the Doctor and Nyssa must solve the mystery before the City of Light is overrun.