Doctor Who month brings Tread Perilously to "Earthshock," the infamous Fifth Doctor episode in which we learn who really killed the dinosaurs.

When Adric and The Doctor have a fight about teenage angst, the TARDIS lands on 26th Century Earth, where the group encounters an army detachment investigating the recent deaths of paleontologists. Somehow, it all connects to a freighter light years away and crew worried about losing their bonuses. But is their cargo the real power behind these events? And will Adric chart his way home or will tragedy claim him?

Justin's opinion of the Fifth Doctor remains unchanged. He also learns the truth about Tegan's accent. John Nathan-Turner's decision-making once again creates problems. Nyssa gets compared to Zoe. Her fashion choices also come into question. Erik defends Tegan and Peri as good characters. He also presents a new philosophy toward remakes. Justin is excited to see a quarry. The future guns and armor get positive remarks. The Room gets invoked to explain a point about directing. Justin comes to hate Adric and agrees with Steven Moffat's opinion of the character. Erik's "In the Year 2525" joke fails to land. He also learns about "insectivores." Fridge logic gets applied to certain aspects of the story and the Cybermen make a special appearance.