Stranded in the jungles of Kembel, the most hostile planet in the Galaxy, Space Security agent Marc Cory has stumbled across the most deadly plot ever hatched - the Daleks are about to invade and destroy the Universe. Cory has to get a warning back to Earth before it's too late - but the Daleks find him first. Months later the Doctor and his companions arrive on Kembel and find Cory's message. But it may already be too late for Earth - the Daleks' Masterplan has already begun.