Donald Duck reluctantly takes his nephews Huey, Dewey and Louie to the home of their reclusive great-uncle Scrooge McDuck. Enthralled by their once legendary great-uncle and the wonder of McDuck Manor, the triplets and their newfound fierce friend Webby learn of long-kept family secrets and unleash totems from Scrooge's epic past, sending the family on an adventure of a lifetime to the Lost City of Atlantis.

The nephews take Webby to Funso's Fun Zone and have a dangerous run-in with the Beagle Boys.

After crashing Ma Beagle's birthday party, Webby and new mysterious friend Lena must fight their way through Beagle Boy turf to get back home.

In a lost pyramid, Louie interprets a pharaoh's prophecy to his advantage, forcing Scrooge and Launchpad to convince a group of living mummies to rescue him.

Donald is dragged into a feud between Scrooge and Zeus, while Dewey and Webby search for an artifact that may provide the truth about Dewey’s mother.

When Dewey invents a holiday that allows the triplets to be only children for a day, each realizes they need their brothers more than they thought.