Emissary of the Daleks

On the planet Omnia, a young man leads the Doctor and Peri through the battle-scarred ruins of a city. Among the rubble he shows them proof that their invaders and new masters, thought to be invincible, can be defeated. The proof is the blasted, burnt-out remains of a Dalek.

But this is a Dalek-occupied world like few others. For one thing, there are few Daleks to be seen. And for another, the Daleks have appointed an Omnian, Magister Carmen Rega, to govern the planet as their emissary.

Why are the Daleks not present in force? And can the Doctor and Peri risk helping the Omnians, when the least show of resistance will be met with devastating reprisals from space?