Penn must overcome his jealousy of popular fellow cadet Blaze to complete his mission and finish at the top of his class at Dragon Flight School.

Phil and Rippen tunnel into The Odyssey and damage the Multi Universe Transprojector, causing unbalance in the multiverse. Vortexes form in every world that Penn and his team have visited. Penn, Boone, and Sashi must travel to each world and close all of the vortexes before everything and everyone from all the worlds get sucked into nothingness. During their mission, Penn finds a crystal shard in the nothingness, which, according to Phyllis, is the key to finding his parents.

The trio return to the dragon world which finds itself under attack by winged unicorns which threaten to destroy Wingfire Academy. However before the team can fight them, they must get Blaze, who has fallen into a slump from a previous defeat by the unicorns, back on his feet to help them.

Penn, Sashi, and Boone must travel to the three most dangerous places in the multiverse in order to free Penn's parents as Rippen plans to conquer the Most Dangerous World Imaginable with Larry and those with him after having to close its portal from the other side.