Molly Hale is a little girl from the town of Greenfield, the daughter of two researchers.
In the movie Spell of the Unown, both her parents disappear; first her unnamed mother, then her father Spencer, leaving her in the care of the family servants. Her father left behind a mysterious puzzle box with Unown letter tiles.
Molly uses the tiles to spell the names of people important to her, and when she begins to cry, the Unown spring to life and grant her wish.
The town is engulfed by crystal, enveloping everything and driving everyone but Molly from the mansion. Molly's wish for better companionship brings about a bizarre entity -- just before he had left, Spencer had read her a story about the great volcano beast Entei, and so the Unown summon a spectral Entei to serve as her father.
Molly decides she needs a mother as well, and has the Entei bring Delia Ketchum to her. Delia is hypnotized into believing that she is the girl's true mother until she sees her son Ash risk his life to enter the crystallized mansion. Since that moment, Delia tries to reason with Molly, helping and protecting her through the movie.
Molly takes three forms over the course of the movie -- her true form as a small child, a pre-teen to battle Misty, and a teenager to face Brock. The last two were crystalline like Entei, and can be interpreted as a physical manifestation of her dreams while her real body is asleep in her bedroom.
By the end, Molly realizes what her wish is doing to those around her, and the false Entei sacrifices himself to drive away the Unown.
She is not alone for long, as her father, and later her mother, both returned soon.
During the end credits, she has a real Pokemon, a Teddiursa.