The Doctor and Medok protest to the guards that he has indeed witnessed the Macra, but they refuse to believe him, he's sent to see the Pilot. Medok's statement saves the Doctor's bacon, he protests his innocence. The Pilot is given a message by control, 'there is no such thing as Macra,' and that the visitors must undergo processing. In their sleep they hear a soothing voice telling them that the colony is perfect and that they're to be given work. The Doctor gets to Polly in time, but Ben falls under the spell, Jamie did not. Ben turns on his friends, elsewhere Medok is refusing to fall to the processing, he chases after Polly, who witnesses a Macra which sets on Polly.
As with the opening episode it's a fun continuation, it's a good character driven story, the TARDIS regulars get to have some fun, Ben and Polly are brilliant, it's one of their strongest stories. The Colonists are well created, Peter Jeffrey is fun as the Pilot, and Terence Lodge is good value as Medok.
It's not in my top three of Troughton's outings, but it's a fun story. I would love to see how the Macra were realised. 8/10