1. There's a presumably alien base, presumably on the Moon. It's viewable from Earth, if you know where to look with a strong telescope, and the episode begins with a great shot of what presumably is a prisoner workforce on the Moon, and a shot of the blue Earth marble in the black. Very effective.
2, There are transit zones between the colonies on Earth, transversable via passes issued by whoever it is that's ultimately in charge, presumably, again, the aliens. We sort of knew this already, but now it's explicitly spelled out.
These details are tantalizing and crucial, given to the viewership as if on a strict need-to-know basis. Unfortunately, I for one would like to know much more already.
Meanwhile, the action in the colony heats up with some well motivated deaths - that is, killings which make sense, however shocking they may be. This makes Colony a taut narrative, even though the deaths of fairly major players is becoming somewhat predictable, in the way that they became in the final year of the original V series (not the preceding, superb mini-series) some decades ago.
There are only two episodes left this season, and the coming attractions promise that we'll finally find out just whom our heroes are fighting. It's notable and even amazing that we haven't seen any alien in the flesh so far - just presumably their super ships and now the Moon base. Maybe they're not flesh-and-blood - maybe they're robots. Or maybe they're not really aliens but some advanced kind of humans.
I'm looking forward to the next two weeks.
See also Colony 1.1: Aliens with Potential ... 1.2: Compelling ... 1.5: Questions ... 1.6: The Provost ... Colony 1.7: Broussard
not exactly aliens, but strange enough ... The Silk Code