Last night on Fringe, the show returned its focus to The Other Side as the shape-shifters return to steal portions of people's brains. They are attempting to recreate memories of the construction of the door back to The Other Side.

As Olivia and Peter race against the clock to track down the inter-dimensional baddies, Walter and his own memories are at risk. A new villain rears his (unfrozen) head, but will his cunning cost Walter his life, or will the team be able to save the good doctor?

Read our recap of "Grey Matters" if you need to get caught up, then see if you agree with our review of the episode, and what we felt worked and what did not, below:

What Didn't Work: The Tracking Device
In all honesty, just about the only thing that didn't work in this episode was the tracking device Walter implanted in his neck. When the genius goes missing and the tracking device is removed, Peter has to rely on his own smarts to find his father. Granted, that tracking device probably would have worked fine if Walter had, say, wandered off in the grocery store, but we're dealing with villains who can cross dimensions; a GPS tracker barely buried underneath the skin is not going to work against these guys.

What Really, Really Worked: Walter Bishop's Readmission
We loved Walter having to take on a case involving insanity. We laughed at his quips - upon arriving at the Hennington Mental Health Institute, he makes a point to tell the guard that he's "perfectly sane." Later, when told that his requested amount of valium is a high dosage, he cooly points out that he has a high tolerance. He even has a special album that he listens to to bring him down off a valium high. But we also watched Walter struggle with his own insanity when forced to confront the idea of mental health. He confides in Astrid that he has often searched for "a remedy for insanity" and then admits that searching for such a thing is a fool's errand. Our hearts broke a bit when he asks Newton if he plans on "curing" him. As Peter points out, Walter is just sane enough to know what his insanity has cost him.

What Really, Really Worked: Thomas Newton's Resurrection
The episode revolved around Thomas Newton, the former frozen head and leader of the shape-shifters that William Bell warned Agent Dunham about. We know that this man (or whatever he is) is supposed to bring about the end of our world, but damn if he isn't incredibly polite while doing so. He apologizes to Joseph Slater for having to operate on him, and seems to hold great respect for Walter Bishop even as he tortures him to get answers on how Walter was able to build a doorway between the two worlds. He is even calm as Agent Dunham points her gun in his face. Like all great villains, Newton is not a frothing-at-the-mouth, mindless mad man. What is so chilling about Newton is just how human he appears to be. But make no mistake about it, he is true evil. When Dunham chooses to save Walter at the expense of letting Newton escape, he keeps his side of the bargain and gives Dunham the antidote for Walter's poison, but then snarls into the phone, "Now I know how weak you are." We hope that Fringe will return its focus on this Other Side storyline full-time, not only for the good of the show, but because it means we'll be seeing a lot more Thomas Newton every show.

Steve Marsi is the Managing Editor of TV Fanatic. Follow him on Google+ or email him here.