The Spear of Selene! is the tenth episode of the Disney XD animated series, DuckTales. It aired on May 4, 2018, on Disney Channel
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.
Scrooge, Donald, Launchpad, and the kids were flying through a lightning-filled storm. Everyone was nervous about their situation, but Launchpad remained calm and did his best to keep them safe. Yet on the side, Dewey was fiddling with the plane's gears, causing a flashes red light bulb go off. Launchpad doesn't think it's anything to worry about, but then Dewey caused him to worry about it, purposely crashing the plane into the Greek island Ithaquack. With Scrooge and Donald having no interest in being there they try leaving immediately, but Launchpad wants to find out what wrong with the plane. Webby suggest that they explore, but Scrooge and Donald tell them to stay on the plane but they take off anyway. While Huey and Louie go off to play Webby pulls Dewey aside to discuss their plan to search for the Spear of Selene; the artifact that was taken by Della Duck when she disappeared. They hope once they find it and learn what it is, in hope that it could tell them what happened to Della.
While Dewey and Webby runoff, everyone else remained on the beach, Donald tries to get to get Huey and Louie back to the plane but Donald was then tackled by an old associate: Storkules. Storkules is overjoyed to see Donald and his family, although his father Zeus isn't happy about Scrooges return.
Meanwhile, Dewey and Webby went searching in the Temple of Heroes to search for the Spear of Selene, during the search Webby has made a theory that Della stole and betrayed the family, but Dewey is against the idea and wishes to see his mom as a hero.
Back at the beach, Zeus reminiscences of when Scrooge was there last, Zeus is annoyed because Scrooge out bested him in everything making him bitter; as he was once the god of hospitality and now the god of thunder. Zeus tells that everyone left after Scrooge and family did, and because Zeus couldn't beat Scrooge it made him so angry that he took it out through a year-long lightning storm that at most caused everyone to leave. Although Sturkules was happy to have Donald back, only to then realize Della wasn't there and he asks where she was, but Donald just had sorrowful look. Storkules understood that something sad happened, so to cheer him up he wished to venture again in Della's honor, but Donald confesses that he doesn't go on adventure anymore so instead they all have a party. Zeus was hesitant at first but then agreed. Some were enjoying the party but once Scrooge complained about the chips Zeus became enraged that he isn't "good enough" for Scrooge, so to lighten the mood Storkules suggest playing games, Zeus takes this opportunity to challenge Scrooge and his family in a contest to finally beat Scrooge. Scrooge and the Duck Family try to leave, but Zeus ultimately stops them by creating a force field of lightning surrounding the island.
Zeus puts Donald, Huey, and Louie against Storkules in a race towards Aeolus Bag of Winds, Donald doesn't want to participate in the petty rivalry and tries to bail but, when the bag was open he was swept away by the wind inside. Though their wits, Huey won the challenge and had Storkules to congratulate them, unfortunately, his father doesn't take it well and demands more challenges. Through the other challenges, Donald won most of them through dumb luck, leaving Zeus more and more frustrated. In the next challenge Zeus tries to get them to steal the Golden Fleece from a little girl, Storkules is conflicted by this and tries to ask Donald for help. Donald refuses to take part in another adventure stating with bitterness that someone always gets hurt, Storkules is shocked by this states that Della wouldn't take that, this upsets Donald and walks away in sorrow.
In the Temple Dewey and Webby travel through many chambers all to be the wrong one, but then they finally end up at the right one after they got help from the Kraken. Finally in the right place Webby reads a prophecy that made her theory of Della to be plausible. Dewey doesn't want to believe it and when Webby tries to go into the Garden of Selene, Dewey refuse by blocks her now wanting to end the search, Webby refuses and they get into a fight. Back at the beach Storkules is still conflicted by the challenge but the Louie don't see it as complicated until the child starts to sing revealing that the child is actually a mind-controlling siren everyone avoid her sing except for Storkules. Zeus then tell Storkules to destroy them. When Donald tries to get back to the plane he hears the kids crying for help and immediately running back to protect them.
In the Temple Webby finishes the fight and then asked Dewey why he preventing them to learn the truth, he breaks down and confesses that he's scared of what the answer really is; if his mother really is a bad person who left them for a selfish reason. Webby understands and with her sympathy, agrees to end their conspiracy. This gives Dewey a choice to walk away, but instead takes Webby’s hand and jumps into the garden together. While in the garden, they run into Selene, the goddess of the moon, who was expecting Della Duck. Dewey ask her where the Spear of Selene is, Selene didn't know what they were talking about because she never had a spear, Selene had then realized that Dewey was Della’s child because he was just like her. Dewey had then fallen into despair when they didn't get any answers about the spear or his mother, returning to the thought that she could be a bad person. But then Selene comforts Dewey by displaying a memory of Della through her sphere and tells Dewey that his mother is a good person who loves her family. Selene gives Dewey of Sphere of Selene and tells him not to give up, to hold on to the spirit he shares with his mother, with all the warmth he was given Dewey graciously hugs Selene and pulls in Webby to the hug as well.
Meanwhile, at the beach Donald fights Storkules all goes well but then Storkules gets the upper hand, although Scrooge had than tagged in and enjoy it, stating that it was like old times and Donald smile at this. While they fought Louie than persuade the siren to stop singing thus bringing back Storkules to his control. Once Storkules return from his brainwash self to his cheery self and then he hugs Donald with great gratitude. Scrooge then turns to Zeus and tries to settle a truce and end their rivalry, but Zeus refused desperately wanting to beat, so Scrooge purposed a finale game where the winner gets all the glory. In the finale game, Scrooge lets Zeus win to finally end the rivalry making Zeus finally happy and confident again. Afterward, Storkules walks up to Donald telling him that even though he may be done with adventure, but it will never be done with him and no matter what, he will always be a hero, Donald is touched and thanks Storkules by calling him a friend, which made Storkules very happy.
Dewey and Webby make it back at the beach meeting up with the family, before heading to the plane Dewey promises to remain in the search with her, so together they will learn the mystery of Della Duck. Although at that moment Dewey drops the sphere and accidentally wins the game against Zeus, which he was infuriated about thus creating a storm. The family runs to the plane to find it torn apart with Launchpad believing that he "solved" the problem.