Pages with tag and Jon Pertwee
Doctor Who: The Three Doctors, William Hartnell, Patrick Troughton, and Jon Pertwee
In this, the first multi-Doctor story, we see a situation so dire that the Time Lords must bring together multiple incarnations of The Doctor. The name Gallifrey had not been revealed yet, but the Time Lords "home world" was under attack by Omega. Omega was the Time Lord who developed the time experiments which gave Time Lords the ability to travel throughout time. However in the process Omega was trapped in an alternate dimension, and sought revenge.