A fanfic by Galen Hardesty.
While walking home from the library in Highland, Texas, young Daria Morgendorffer finds an orphaned baby opossum near her mother and siblings, who were very recently run over by a car. She adopts the opossum, names him Opie, and cares for him until his presence is discovered and it becomes clear he cannot stay at home with her.
The story offers a view of young Daria as a child who cares about other lives, and though she views things in a detached and intellectual way her strong nurturing side is brought to the fore.