Not that the first three episodes of the season weren't without merits. Actually, although they did suffer somewhat from the abrupt and acrimonious departure of Gideon, they weren't bad at all and did their best considering the difficult circumstances behind the scenes.
Here though in "Children of the Dark", things feel much more settled. Contrary to another review, this reviewer does not think there was an intent in demonizing the foster care system. Actually it is a system that has taken some stick but actually considering it's not an easy job and have to cope with many troubled circumstances the foster care system does a great job, and this reviewer is sure this show will agree to that. This said, what the intent of the episode was was most likely making the point that the system is not without its flaws and that situations like this (though not as extreme) can happen, it may seem like a one-sided view of the system but it to me was a realistic one and speaks volumes about things not appearing what they seem.
"Children of the Dark" improves on the previous three Season 3 episodes and the first great one. Not among the best of 'Criminal Minds', but one of the most disturbing and emotional roller-coaster-like episodes not just of the season but of the earlier seasons too. Another thing that "Children of the Dark" has gotten some heat for is for showing the unsubs' identities early on.
Admittedly, the show is better when the criminal is revealed later and the case takes longer to unfold, making things more suspenseful and mysterious, but actually this is a case of this not being an issue for me. There have been episodes where it has mattered, like Season 11's "The Bond", that focus too much on the unsub (that could not been interesting), wastes the BAU, side-lines things like profiling and such and in general the case isn't compelling.
Why this potential problem is not an issue here in "Children of the Dark" is because the early identity does help one really get to know the unsubs and why they're doing it and despite what they're doing develop strong feelings about the situation. "Children of the Dark" still feels like a 'Criminal Minds' episode, the BAU have plenty to do, the chemistry and character moments are interesting and adorable and the profiling is as ever intelligently done.
Enough focus is put on the unsubs to get one feeling both menace from and sympathy towards them, and the case is actually extremely compelling with a lot of tension and suspense, a disturbing and harrowing edge and induces a roller-coaster of emotions by the creative twist at the end, which contains some of the episode's most powerfully acted moments (especially Morgan with the boy).
The episode is made with the usual high-production values, scored with the right haunting but melancholic vibe, directed solidly and written thought-provokingly and smartly, on top of its near-perfect execution of a difficult story. The characters are interesting and well-written, love what was done with Prentiss which saw a softer side than what was seen before with her earlier on in the show. The acting is spot on from everybody.
All in all, powerful episode and the first great third season episode. 9/10 Bethany Cox