This issue continues the current plot arc that sees Derek Dynamo dragged to Inner-Earth by the Exile, one of the series' key antagonists. In recent issues, Derek discovered that the Exile belongs to a race of people called the Reptiloids. The Reptiloids have an advanced civilization in the dinosaur-infested Inner-Earth and, by and large, don't believe in the insane theory that there is an "Outer-Earth" warmed by a distant star and not plagued by dinosaurs. (I mean, let's be honest, that does sound kind of far-fetched.) The Exile hopes to prove to his people that Outer-Earth exists using Derek as evidence, but some Reptiloids don't want to hear his message – or give him a chance to tell anyone else.
Meanwhile, Super Dinosaur and Derek's other friends continue their journey through Inner-Earth in search of the kidnapped hero, contending at every turn with the dinosaurs the Exile wants to escape. It's amusing to witness SD's reaction to normal dinosaurs, since he's never encountered one, and part of his whole character arc has been about feeling out of place because of his species.
Caught up? Cool.
As much as I enjoy this series as a whole, I do have to say that I'm not digging this arc as much as I'd like. Inner-Earth has been talked about since the beginning, and as we've gotten to see it these last few issues, it's kind of what you'd expect: very Lost World. And, that's fun. But, the Exile's pseudo-political plot suffers, in this issue more than ever, from weird pacing: one moment seeming very slow and wordy, the next feeling like things are happening too quickly. It does not help that he's kind of wooden, and even though the revelation of his motives makes him more anti-hero than villain, he's as unlikeable as ever. Basically, this plot doesn't play to the strengths of the series or Kirkman in general. But, maybe this is an important plot development for the future. Depending on where the series goes from here, I could see this being worthwhile in the long run.
If you haven't been reading Super Dinosaur, I urge you to give it a try, especially if you're either a) 8 to 12 years old, give or take, b) a relative of someone who is, or c) nostalgic for the kind of stories you loved at that age. But, don't start here. It's generally stronger than this.