The planet Androzani Minor, the distant future. In the planet's caves war rages between government troops and the android warriors of the mysterious Sharaz Jek. But what makes spectrox, the substance they battle to control, so valuable? And how far will the Doctor go to protect his companion?

The Doctor and Peri have been rescued from the firing squad by the mysterious Sharaz Jek. But he has his own plans for them. And why are they suddenly feeling ill?

The situation on Androzani Minor is building toward a violent confrontation, and the Doctor and Peri are slowly succumbing to spectrox toxemia.

Events on Androzani reach a bloody climax. Will the Doctor and Peri survive the carnage? And at what cost?