The Ark in Space: Part Four
- Episode aired Feb 15, 1975
- TV-Y
- 25m
The Doctor tries to protect the humans still in cryogenic suspension from the Wirrn, who are determined to use Earth as their new breeding ground.The Doctor tries to protect the humans still in cryogenic suspension from the Wirrn, who are determined to use Earth as their new breeding ground.The Doctor tries to protect the humans still in cryogenic suspension from the Wirrn, who are determined to use Earth as their new breeding ground.