NEW YORK — Kevin Spacey is in final talks to star for Steve Reuther’s Bel Air in “Pay It Forward,” a film to be directed next year by Mimi Leder.

Based on a novel by Catherine Ryan Hyde, story centers on an unusual trio: a teacher who is physically and mentally scarred from child abuse (Spacey), his student and the student’s mother. Spacey is the first to be cast, but Bel Air is out to top actresses to play the mother, with Helen Hunt among those mentioned. Warner Bros. will release the film.

Leslie Dixon (“The Thomas Crown Affair”) adapted the novel, which draws its unusual title from a system of goodwill implemented by the young student as a way to improve the world. If a person does you a good deed, you pay it forward by doing something nice to someone else.

Having come up with the system when challenged by his teacher to change the world, the kid tests his system by taking in a homeless person, and the boy’s mother, herself emotionally scarred, heads right to the school to complain to the teacher. They develop a relationship. All the while, a journalist tries to figure out the origin of the pay-it-forward system of good deeds, which is transforming a gritty little town. The story is gritty but uplifting.

“It’s so difficult to find a movie that shows optimism that isn’t forced,” said Reuther, who hopes to start production in mid-February. “Each of the characters is a real, flawed human being, and Kevin was our first and only choice for the role,” said Reuther.

Spacey is coming off a Tony-nominated Broadway run in “The Iceman Cometh” and a critically acclaimed performance in the Sam Mendes-directed “American Beauty.” His Trigger Street Prods. just produced “The Big Kahuna,” a project which took root at Lion’s Gate. Spacey and Danny DeVito star as salesmen at an industrial lubricants convention in Wichita, Kan.