After three episodes that tried — and essentially failed — to recreate the appeal of the beginning of the season, Terra Nova's got back on its feet. "Proof" not only worked as an episode, but it did so by succeeding where "Nightfall" and others failed: it developed several independent storylines that each had some value and that definitely put the Shannon family at the heart of things, a combination I was starting to doubt the show could achieve.
Maddy showed some promise at the beginning of the season, but then was either underused or paired with her soldier, which never quite brought the best out of Naomi Scott, who plays the teenager. With the love interest away, things looked much better as her story had no choice but to draw from her brainy side, one of the two things that made the character appealing in the first place. Her encounter with Ken Horton and the investigation that followed was, above all, a well-structured story. It brought in a character (Horton) that had enough gravitas to actually be seen as a great figure to prospective scientists. Then in an early move, the story showed he didn't get along with Malcolm, smoothly planting the seeds for one of the funniest moments of the hour (Malcolm, upon discovering the unauthorized DNA test Maddy was performing was on Horton: It'll go faster if I help!). Finally, the integration of Zoe into the story was clever, providing more humor, but also clearly building on the relationship between the two sisters and on the other appealing thing about Maddy: her personality.
She wasn't talking to Zoe as much as she was speaking to herself during those conversations with the youngest Shannon. Such scenes work with Maddy, because she often appears not as grounded in reality as other characters, which is why it is so odd to see her with the soldier. He doesn't come across (so far) as someone who could help nurture that side of her. That aspect of her personality also explains why the episode's ending scene, showing her smiling while looking at the beautiful apple (without mold), worked.
The storyline involving Josh, besides giving its title to the episode, had a definitive impact on the overarching story. After an illness swept over the Sixers camp, Mira called in her favor, asking Josh to steal some medicine from the infirmary using his mother's pass. Maddy's soldier and Josh's Kara are typically used by the story to give the two Shannon teenagers conflicting values and get them to act out of character. The show has had more success with Josh because of the presence of Skye, and now, Josh's connection with the Sixers makes the Kara subplot even more interesting. We haven't seen enough to conclude one way or the other, but it would be better if Mira didn't learn the full story and still kept her end of the bargain by bringing Kara to Terra Nova. Skye's reaction was one of the best things about the storyline and her relationship with Josh now almost requires Kara to come to the settlement.
I think we have it established that CGIs are not the show's strongest point. Except for very rare occasions, dinosaurs have always been lacking a final touch that would make them really fit into the landscape, and the fish wasn't much better. In fact, the whole fishing expedition and its male bonding moment up to Taylor's reckless decision to stay alone was odd.
Although this was one of the best episodes of the show so far, there were a couple other things that didn't particularly shine: things like Taylor facing the "komodo", Josh's reaction when the hologram of Kara disappeared, and Maddy running after Ken Horton (who had her sister) instead of going to her dad with the full story at that point. And finally, I would very much like to know what happened to the spider which was about to bite Maddy...
"Proof" moved with baby steps on the Sixers storyline, bringing us what looked like a way to communicate through the time fracture with 2149, but what really stole the show was the standalone story involving Maddy and her "Marco Polo, Darwin and Shackleton all wrought in one". Both stories helped deliver an episode that could be described as Terra Nova's formula done right.