Considering the season, it seems appropriate to touch upon The Nutcracker, that ubiquitous Christmas ballet, which was actually based on a 19th century story by E.T.A. Hoffman. I haven’t seen this since childhood, however, so this will be a brief entry.
The Nutcracker probably only qualifies as an Honorable Mention as a Girls Underground story, but there are some definite elements present. Clara is initiated into the otherworld via a toy given to her by her strange godfather. When the toy is broken by her brother, she cares for it. That night, another world grows up around her, and in the midst of a battle between gingerbread men and mice soldiers, her beloved Nutcracker (now life size) is threatened by the adversary, the Mouse King. Clara intervenes and saves the Nutcracker, who becomes a handsome prince. She eventually becomes the Queen of a fabulous kingdom of sweets.
For a more thorough investigation of The Nutcracker as an archetypal katabasis story, and Clara’s relation to several other GU heroines from Alice and Dorothy all the way back to Persephone and Inanna, see Catherynne Valente’s essay “Follow the Yellow Brick Road: Katabasis and the Female Hero in Alice in Wonderland, The Wizard of Oz, and The Nutcracker Ballet” [Word doc from her website].