Doctor Who And The Mutants

What was happening to the people of Solos? Why are they gradually turning into Monsters? Hands that become claws, flesh that turns scale-like...

When the Doctor meets the Marshal and Jaeger, he realizes that all is not as it appears to be. The Marshal has a sinister plan to gain control of this planet, and it's up to the Doctor to save Solos from this mad earthman, as well as save the Solonians themselves.