At the end of the day...is there any reason for this episode to exist? I guess the answer is "character stuff" but we don't really learn much that wasn't more or less obvious.It's hard to shake the feeling that all of this could have been covered in a scene or two of exposition (at the end of it, we're apparently no more than a few minutes further on from where the previous episode ended).
Instead, it's used as an excuse to have all the characters dress up in silly costumes and pretend they're teenagers.No real explanation is given as to why the aliens look about eight in 2004 and about twenty in 2008.We have children's homes run by abusive nuns in 2004, because that was "the past" and that's what happened in "the past".It's tempting to put Liz's dad using a camera that would have looked old in 2008 in the same category, but we then cut to a digital camera being used at the prom, so that's probably deliberate.
The other problem with this episode is it's hard not to feel like this would have been a good first episode and then we could have spent the rest of the series dealing with the fallout.Instead, it's stuff from ten years ago and it's too late to deal with the consequences.
Also, in the original series, the bad guy alien killed an innocent person and faked a car crash to cover it.Here, the supposed good guy aliens did it.That says a lot about what's gone wrong with television and society.As does the reuse of the "murdered a would-be rapist" idea from the awful Tomorrow People remake.
There's a Tess mentioned, which could be important or could just be an in-joke. Oh, and no sign of teenage Maria.She really is only in the show because she's in the books.