Tom and the others debate how to keep the dragons a secret, even as a rambunctious young "cloaking" dragon gets loose in town and pursues a friendship with a reluctant Alex.
Tom and Jun encounter unexpected dangers and are separated while exploring the Hidden Realm of dragons. Tom introduces Jun to the dragon world, and Jun bonds with a dragon of her own.
Tom and the Riders vow to help Thunder face the dangerous dragon who attacked the King's Realm: a fierce and unpredictable Snow Wraith who has made its way from the Ice Realm.
When a deep freeze puts the lives of everyone in Rakke Town in jeopardy, the riders must attempt to use the dragons to get everyone through the night without being seen.