The planet Peladon is hoping to join the Galactic Federation.
With the commerce of the world grinding to a halt, the Doctor, Jamie and Zoe agree to investigate and set off for the Moon in an old fashioned rocket.
On the Moon, the Doctor is captured by the Ice Warriors and learns that they intend to use T-Mat to spread a deadly fungus across the world.
The work of the committee is hampered by sabotage, fear and suspicion. The Doctor knows the Ice Warriors of old and believes that they may be the guilty party.
Returning to the Moonbase, the Doctor confronts Slaar and the remaining Ice Warriors and must find a way of deflecting the invasion fleet that is heading towards them.
