sentences:  The 90-minute single-part story was commissioned on 2 August 1982 and would involve the various Doctors and companions drawn to the planet Maladoom where they are trapped by the Master who is working for the Cybermen.The Cybermen want to isolate the genetic material that permits Time Lords to time travel freely so that they can incorporate that information into their own biology.The First Doctor would be revealed as an android, hence the title being the "Six" Doctors.