Donald arrives in time to join Xandra and the Caballeros and the four of them charge the basement of the mansion, while Felldrake gives Sheldgoose powers of his own to stall them while he reaches his full power. Sheldgoose's attempts to summon evil allies from their past adventures are countered by the Caballeros's own allies, and they arrive in time for Felldrake to awaken and destroy the Institute. The Caballeros try to fight Felldrake but are overpowered and pushed to the verge of defeat. In their last moment, they are contacted by Blazebeak, an ancient wizard whose power had been protecting them through their amulets. With his power, the Caballeros attempt to banish Felldrake back into his staff, but Sheldgoose destroys it out of panic and inadvertently restores everything to normal. His true nature exposed, the boardmembers strip Sheldgoose of his presidency and Donald is named the new Acting President to everybody's happiness. As Sheldgoose escapes on Leopold, he finds that Felldrake is now trapped inside his own body, and Felldrake decides to call in a favor from an "old friend"

Daisy's patience with Donald has run out, so Xandra books them for a vacation in Shangri-La to help solve all their problems. The Yeti resort staff have orders to not let Donald leave until his temper has been dealt with once and for all, leaving him unable to help the other Caballeros as they begin a final assault on Sheldgoose's mansion to stop him from reviving Felldrake.

With the Caballeros back among the living, Xandra takes them and the nieces to Camelot to get them some proper "hero training" from King Arthur himself, but the King's purely-motivational training leaves a lot to be desired when the nieces accidentally summon a dragon. Meanwhile, Sheldgoose breaks into the Caballeros' cabana to steal back the Spark of Life. Though he is foiled by Ari and the bear, he manages to steal the amulets instead.

The Caballeros are dead and trapped in the Underworld. As they try to escape, they find Clinton Coot, the one who left them the cabana in his will. He explains the history of the original Caballeros and how he spent his whole life following their exploits, then helps them find a way to return to life while newly-appointed Underworld managers Sheldgoose and Felldrake attempt to stop their escape. As the nieces attempt a seance to contact the Caballeros, Xandra goes to the Underworld herself to rescue them. With her help, the Caballeros return to life on Earth, while Felldrake and Sheldgoose are kicked out of the Underworld for being bad employees.

The Caballeros are heading to Mexico after noticing Felldrake's activity there, but Donald has another date with Daisy and he can't be there in person. The nieces agree to help him by posing as Donald while he speaks to her from Mexico through a pair of magic mirrors, but this backfires and Daisy becomes even more furious. In Mexico, the natives revere and worship Panchito as a mighty warrior before throwing him into a ritualistic wrestling match against Sheldgoose. When the other Caballeros and Felldrake interfere with the match, the God of Death appears and kills them all as punishment for breaking the rules.

To stop Felldrake's new plan, the Caballeros and Xandra travel to the Nazca Lines and enter a world of two dimensions where chalk drawings come to life. However, it ends up being a trap and the Caballeros must escape before Felldrake and Sheldgoose erase them forever. Meanwhile, April, May, and June sneak into Sheldgoose's mansion and make some shocking discoveries.

After retrieving the Spark of Life that Lord Felldrake intended to steal from Mount Rushmore, the Caballeros are assigned to guard it while Xandra and the nieces are at the Institute soirée. When they get bored, they stuff it into the cabana's bear rug, bringing it to life. As the Caballeros try to catch the bear as it seeks food, Xandra crashes the soirée, Sheldgoose deals with the Institute boardmembers who demand explanations for his absences, and Daisy shows off her new boyfriend Dapper Duck to Donald's anger.

The Caballeros head to Stonehenge, which is the secret portal to Goblin Town. Once inside, the new Goblin King Felldrake sentences them to Goblin Jail and then demands that the goblins go to war. When their weapons prove unsatisfactory, Felldrake unleashes an unstoppable war beast. The Caballeros must recover Xandra's book and escape Goblin Jail before the beast reaches the portal back to Earth.