Ambush / Obert Skye.

Enhanced descriptions from Syndetics:

What can happen on an innocent field trip to a museum? In the secure protection of a jail? Or on a simple bus ride? Plenty, if you are a member of the Pillage family and your name is Beck Phillips. No matter what strangeness is going on, Beck still manages to turn things on their head.
When Beck's personality and behavior begin to change after he makes a fateful, life-altering decision involving what else? a dragon egg, there is no one around to stop him from fulfilling his family's destiny set out in "The Grim Knot." And as life in Kingsplot moves unwittingly toward the brink of another dragon disaster, Beck finds himself living a life of deception as he hides information from the people who love and care about him the most.
In this final episode of the "Pillagy" series, with the destructive forces of his family heritage running strong and unhindered, Beck must now face the truth and rise to the challenge of stopping the madness or succumb to the draconic chaos he has helped create."