Arriving in an underground cave system on Earth in the 26th century, the Doctor, Adric, Tegan and Nyssa find themselves caught up in a military investigation of the disappearance of a scientific team led by Lieutenant Scott and Professor Kyle. Two dark figures are stalking the troopers in the underground caves. The Doctor and his companions offer to help, but Scott thinks the Doctor to be behind the murders. Written by
Did You Know?
This episode was watched by 9.1 million viewers on its original transmission. See more
When the troopers are in the caves, the two dark figures in background walk past (to the right) and one of the troopers stops and turns around. As he does this the shadow of a crewmember can be briefly seen on the left wall. This is not the dark figure's shadow because they have already walked past. See more
Anything we can do to help?
[Scott forcefully grabs the Doctor