The Cyberman have taken over the bridge and they fit a device to the freighter's computer which locks it on course to collide with Earth. The resulting explosion will be so devastating that the entire planet will be annihilated. Tegan gets separated from Scott and his men and is captured. The Doctor argues with the Cyberleader how emotions have their uses, and the Cyberleader responses that emotions are a disadvantage, as he only has to threaten to kill Tegan for the Doctor to obey him. The Doctor and Doberman leave in the TARDIS, leaving Adric, Scott, Briggs and Berger on board the freighter which is getting quite close to Earth. Using his mathematical skill, Adric overrides one segment of the device controlling the freighter's computer. This causes the freighter to jump into a time warp and it goes back back in time 65 million years, but is still locked onto the same co-ordinates. Not only could Earth be destroyed, but with the freighter now back at an earlier point in history, the planet's whole existence could be nullified...