During an attempt to get displaced Fire Gronckles back to their native realm, D'Angelo accidentally feeds them Catastrophic Quaken eggs.

Much to Jun's chagrin, Eugene finally discovers the secret of dragons and demands to become a Rider, but he must bond with a dragon before he's let into the group.

When the Riders discover that Magma Breather is very sick, the only way they can help is to sneak the huge and heavy dragon into the ICARIS infirmary without being caught by any of the scientists.