The Lost Continent (Wings of Fire, Book 11)
Because it turns out the stories are true.
And the other tribes are coming.
The characters are fun and spunky, and have delightful quirks that help readers root for them even when they are a little misguided. Blue's optimism in the face of completely unpleasant living conditions is rather charming, as is his constant battle with following rules when that means dragons he love might not be saved. Cricket, as an "evil" HiveWing shatters Blue's perceptions and endears herself to him by wanting to help him, asking relentless questions, and having secrets her own people don't understand, like growing an extinct tree in her class terrarium project! Swordtail's devotion is touching, and Luna's confusion and fear at undergoing a major change under less than optimal conditions is something which young readers will understand.
The world building is also solid. My best friend in middle school was a huge fan of McCaffrey's Dragonriders of Pern, and was constantly going on and on about different facets of their world. The Lost Continent describes and defines and unique and well constructed dragon world, starting with a map of regions at the beginning, along with the back history of Clearsight and descriptions of the different kinds of dragons. These are the details that readers who want to submerge themselves in imaginary worlds crave, memorize, and endlessly repeat in conversations with other fans.
There's plenty of adventure, traveling across the dragon world, danger, and occasional breaks for honey drops and other delicacies. This series is easier for me to follow than the Warriors, since there is generally a more defined quest centered on a main character with fewer supporting ones. Fans of Park's Wing and Claw series, Rocha's Secrets of Bearhaven and Kathryn Lasky's series like The Guardians of Ga'Hoole or Bears of the Ice will find this newest volume in the Wings of Fire series a worthy follow up to previous volumes.