This review may contain spoilers.

In some ways, "Subject 13" is the sequel to last season's "Peter" (and a deeper look into the discoveries made in "Jacksonville").

It takes place six months after the flashbacks events of that episode, and it takes us deeper into the events that made characters like Peter (Joshua Jackson), Walter (John Noble), Walternate, and now Olivia (Anna Torv) the people that they are now. Unlike "Peter," there's no set-up in the teaser of the story that's about to be told -- "Subject 13" just gets right to it, with no mention of what the Fringe Division (whether it be our Fringe Division or the Other Side's) is currently up to.

Even though we never got a glimpse of our present day heroes, this episode continued to drive home the fact that Peter and Olivia are star-crossed lovers, from the moment they saw each other as children. Apparently, even as kids, they were drawn to each other.

But that wasn't the most revealing part of the episode, no matter how much the writers seem to want to make this romantic storyline an integral (and original) plot. Not even Young Olivia's (aka "Olive") role in Walternate's discovery of the alternate worlds and where Peter went was all that shocking when you come to think about how everything in 'Fringe' is intertwined in a way.

The most revealing part came as the result of original recipe Walter, specifically his insistence on pushing a rather broken Young Olivia to her most heightened emotional state. While we know that both Walter and Walternate are capable of pretty much anything when it comes to Peter, the fact that Walter realizes that Olivia is being abused at home and even seems to genuinely care about her (maybe even the most out of all the cortexiphan kids) but intentionally pushes her into a state of true terror for his own purposes is difficult to stomach. We know that for all of Walternate's mustache-twirling villainy, not even he would do that.

Points of Interest

1. Walter informs Elizabeth that the cortexiphan kids are the only way that he can safely return Peter back to the Other Side, without causing any more problems -- like, you know, Nina Sharp (Blair Brown) losing a hand. Walternate, however, doesn't know that, and we know that, in the present, he refuses to do cortexiphan experiments on children. So the chances that Walternate is actually at fault for the disintegration of the Other Side -- instead of Walter -- is becoming much more likely.

2. It seemed like Young Peter started referring to Walter by his first name (as opposed to his "mom," who he eventually referred to as such) once Young Olivia mentioned "Dr. Walter." Chock another one up to the endless love of Peter and Olivia.

What Worked

Just like "Peter," this week's episode sported the 80s-ish title sequence. One of the best "little" things about 'Fringe' is its attention to detail no matter how seemingly irrelevant, whether it's changing the the title sequence to accomodate to the focus of the episode (like this, and the red title sequence for the Other Side-centric episodes) or just mentioning little differences between both worlds (the Green Lantern versus the Red Lantern, for example).

What Didn't Work

This is about as ridiculous as you can get when it comes to things that didn't work in an episode of television, but when it comes to Young Peter, it's kind of difficult to believe that the child actor grows up to become Joshua Jackson. That's kind of the downside of being a successful child actor who grows up to become successful adult actor, isn't it? That being said, the casting for Young Olivia was absolutely perfect.

Giving Credit Where Credit Is Due

"Subject 13" was written by Jeff Pinkner, J.H. Wyman, & Akiva Goldsman. It was directed by Frederick E.O. Toye.

‘Fringe’ airs Fridays at 9 p.m. ET on Fox.