An unabridged reading of this classic novelisation, based on a BBC TV adventure featuring the Third Doctor. A mysterious power loss strands the TARDIS on Exxilon, a sinister fog-shrouded alien planet. The Doctor meets the survivors of a beleaguered expedition from Earth, while Sarah finds a mysterious super-city and becomes a captive of the savage Exxilons. Worst of all, the Doctor's greatest enemies, the Daleks, arrive on a secret mission of their own. The Doctor and Sarah must risk their lives time and again in a desperate attempt to foil the Daleks and save millions of humans from a horrific plague. Duration: 2 hours 30 minutes approx.