As Eugene continues to investigate the Dragon Club, the Riders come across and subsequently fight the dragon that separated Thunder from his family: A giant Skrill.
Tropes in this episode include:
- Big Bad: The Skrill, as it is the reason Thunder couldn't reunite with his family.
- Heroes Prefer Swords: Tom becomes this starting this episode.
- History Repeats: Let's see: A young Striker-Class dragon and his equally young human friend of viking descent battle a Skrill. Sounds familiar, doesn't it?
- Lethal Lava Land: As the Skrill runs away, it reveals the Fire Realm.
- Lightning Gun: The Skrill shoots lightning out of its mouth.
- The Maze: The Riders battle the Skrill in a crystal maze.
- Shock and Awe: The Skrill, naturally. Thunder, too, of course.
- Wham Episode: Tom finds a spearhead with the same Strike Class symbol on his helmet indicating Hiccup or one of his descendants was exploring the Hidden World long before Tom and his friends.
