If you remember correctly I put The Aztecs in A.
Well the series of very good episodes continues with The Sensorites.
How to say. The beginning is very promising: The Doc who lands in a ship (For the first time in the series, by the way), discovering a mind control problem, and discovering a civilization that seems peaceful but part of which finds that the arriving "humans" are belligerent: WHY NOT. In the future, it will happen, but not at the time: it's an idea.
The resolution of half-crazy humans thinking they are at war with the Sensorites explains everything: the doubt of the fourth Sensorite who himself begins to, let's not lie to ourselves, begins to lose his mind too (Stalin was his man), the poison (And not a bad resolution like yes it was the fourth Sensorite and the city administrator who put the poison blah blah blah)...
Really very good episode, let's hope that the next arc will be as good or even better...