Della makes her animated debut in the series. The mystery of Della's absence in the nephews' lives is a central story thread in the first season of the show, with the ending of the series premiere having Dewey discover a painting, showing that she was previously a companion of Scrooge and Donald in their adventures. Unlike most portrayals of the character, her hair color is now white as opposed to blonde.
Based on flashbacks in the show's tie-in comic, this incarnation was brave, ingenious, and eager during adventures, although her impetuous side led her, Donald and Scrooge into trouble much of the time, much to Donald's dismay and worry. She also wasn't above making light-hearted jokes at her brother's expense.
In "The Great Dime Chase!", Dewey goes to Webby Vanderquack for information about Della, mentioning that Donald had never said more than one word about her and their only memento of her is a photo of Della pushing Donald's face into a cake. Sadly, Webby has little to no information on Della, as if she disappeared off the face of the earth. She mentions that Scrooge bought a mail company the day after they delivered a piece of junk mail turned up at Della's door. Thus, Dewey and Webby go to the archives at The Money Bin but Miss Quackfaster kept stalling them with so-called trials. Eventually, Dewey finds a book titled with his mother's name with the only entry being a reference number, which led him and Webby to a secret room, where they find a letter from Della to Scrooge, revealing she had stolen the Spear of Selene, which was mentioned in "Woo-oo!". Fearing the possibility that his mother betrayed Scrooge, Dewey tells Webby to hold off telling anyone until they know more.
In "The Spear of Selene!", when Clan McDuck crashes on Ithaquack, Dewey and Webby investigate the Temple of Heroes for clues to Della's whereabouts, while debating whether she took the Spear of Selene for nefarious or altruistic purposes. Eventually, they meet the moon goddess, Selene, who tells Dewey that his mother was a true hero and a devoted mother, but has no idea what the spear is, though she insists that Della wouldn't have taken it if she didn't think it was important. To help the two on their quest, Selene provides them with the Sphere of Selene.