EVERYTHING in social studies teacher Eugene Simonet's life is in order - every shirt, every pencil, every person in its proper place.

In contrast, Arlene McKinney is a single mother hanging on by her fingertips, working two jobs and struggling to raise her son, Trevor.

When Eugene gives Trevor's class an assignment asking them to change something about the world that they don't like, it sparks a surprising sequence of events in the new drama Pay It Forward.

Oscar winner Kevin Spacey stars as Simonet, a teacher who doesn't expect his new class to be any better than the last.

"Eugene makes the same speech to his class each year hoping, but not quite expecting, that one of his students will take it to heart," says Spacey.

A man whose physical scars inform much deeper emotional scars, Simonet is nonetheless a passionate teacher.

"He transfers his hope to his students, because he has no hope for himself.

Emotionally, he is completely shut down," explains Spacey.

Yet 11-year-old Trevor takes the class assignment to heart.

"Trevor's mum works a lot and has some habits which infringe on her ability to take care of him, so he ends up taking care of himself most of the time," says Haley Joel Osment - last seen in spooky thriller The Sixth Sense - who plays the youngster.

Pay It Forward director Mimi Leder adds: "Trevor takes this assignment very seriously because his own life is so troubled.

His father is gone; he has to grow up too soon.

He needs some hope in his life.

And he gets it from Eugene."

Inspired by his teacher, Trevor comes up with the idea of 'pay it forward', where people do good turns for three others and then ask them to do the same.

As Arlene begins to see the power in her son's plan, she turns to Eugene for help in understanding him.

Helen Hunt, who co-stars as the mother, says: "She is just amazed by her son.

He has grown into such an introspective, thoughtful young man and she has been so busy.

There is a side to him that she just doesn't know but she wants to know, and she wants Eugene to help her understand him."

"As the story progresses, Eugene starts to allow himself to be more open because of Trevor, and also because of his feelings for Trevor's mother, Arlene," says Spacey.

"He begins to open up and allow himself to be loved."

Since the relationship between Eugene, Arlene and Trevor was the key to making the film work, Leder was inspired by how Osment held his own with the two Oscar-winning stars.

"Haley went toe-to-toe with Helen and Kevin and challenged them both," says Leder.

"He's a truly amazing and very, very honest actor with a knowledge and maturity far greater than his years.

He brought tremendous dignity and honesty to the character of Trevor.

He thinks and feels every word he speaks."