Doctor Who: Summary: The Ambush

After being captured by the Daleks in their metal city, the Doctor, Susan, Ian, and Barbara are trapped and suffering from radiation sickness. The Daleks, confined to their travel machines, need the Thals, a peaceful, blond humanoid race to survive. Susan is sent out to retrieve anti-radiation drugs from the TARDIS. When she returns, she meets the Thals and learns the Daleks plan to lure them into the city and exterminate them. Meanwhile, the Doctor and his companions work desperately to escape the Dalek cells and warn the Thals before they walk into a massacre.