Jun breaks the rules by sneaking a small, adorable dragon out of the Crystal Realm and bringing it home, but finds that her older brother, Eugene, has arrived and watches her every move.
Tom has to keep his mom, Olivia, distracted while Jun, Alex, and D'Angelo use a new dragon to close off a cave leading to the Crystal Realm, and prevent her from discovering the dragons.
Tom and the riders go in search of Thunder and must face a gauntlet of dangerous dragons to find their lost friend. Along the way, Tom reveals his big secret to D'Angelo and Alex.
