The narrator is an unnamed eight-year-old girl with a firm sense of fairness and a deep empathy for animals. She possesses an uncontrollable superpower known as the "Magic Finger" that activates whenever she feels intense anger or witnesses injustice. Adults frequently dismiss her opinions, treating her as foolish because of her age and her struggles with spelling and math. She relies on her magical ability to address the unfair treatment she sees in the world.

Mr. Gregg owns the farm next to the protagonist's home and proudly leads his family in sport hunting. He enjoys shooting birds and deer for fun, failing to consider the feelings of the animals he targets. He is a stubborn, proud man who refuses to listen to children and actively encourages his sons to share his violent hobbies.

A flock of wild ducks that live on the lake near the Gregg farm. They are frequent targets of Mr. Gregg and his sons, suffering heavy losses to the family's sport hunting. After a particularly brutal hunt leaves only four survivors, they begin to exhibit unusual behavior around the Gregg farmhouse.

William is the eleven-year-old older son in the Gregg family and frequently plays with the protagonist. He mimics his father's attitudes toward nature, enthusiastically participating in hunting trips without questioning the ethics of killing animals for sport. He actively mocks the protagonist when she objects to his family's behavior.

Philip is the eight-year-old youngest son of the Gregg family. Despite his youth, he already owns his own gun and eagerly joins his father on hunting expeditions. He shares his family's disregard for animal life and cheerfully joins in teasing the protagonist when she tries to stop their hunting.

Mrs. Gregg is the mother of William and Philip and the wife of Mr. Gregg. She manages the household and supports her family's lifestyle, including their frequent hunting trips. She is quick to panic when faced with unexplainable situations.

Mrs. Winter is the protagonist's school teacher. She is an unkind and impatient educator who resorts to name-calling when her students struggle academically. Her harsh treatment of the protagonist serves as a catalyst for the girl's uncontrollable magical ability.