The first regeneration...
A mercury swamp on a distant Earth colony.
A crashed spacecraft holding a deadly secret. An impostor in the TARDIS?
Polly and Ben watch in stunned disbelief as the unconscious body of The Doctor changes in front of their eyes. Before they can decide if he is genuine or fake, they are plunged into a deadly encounter with The Doctor's greatest foes... The Daleks!
Read the complete script of this classic Doctor Who story, together with background and technical information.