Harrison Ford has his best role in years as a testy scientist who listens to classic rock as he works all night in the lab and who may just have the key to a crucial medicine for a disease that kills children. Brendan Fraser plays John Crowley, the father of two children with a rare genetic disorder called Pompe disease that weakens muscles, enlarges organs, and had a life expectancy of less than eight years. Crowley quit his job as an executive in a pharmaceutical company to start a biotechnology firm to support the most promising research into a treatment for the disease.

That research was being done by Dr. Robert Stonehill (Ford), a twice-divorced, sardonic, and very stubborn professor. Crowley offers him the chance to get the resources he needs to test his theories. He raises the money for a start-up and handles the business side while Stonehill cranks up the Grateful Dead and insults people.

Ford, who bought the rights to the story when he read about it in the newspaper, produced the film and his long-time Hollywood experience and sure sense of story-telling shows. Screenwriter Robert Nelson Jacobs (“Chocolat,” “The Shipping News”) gently streamlined the story to shape the narrative. The Stonehill character is based on several different scientists who worked on the research and some of the most dramatic moments are shorthand summaries of real-life developments. But all of this is in aid of a powerful story that is pro-life in the broadest and most profound sense. Crowley has to ask himself what is best for his children — to be with them as much as possible while they are alive or to leave them for 20-hour days in the hopes of finding treatment that could keep them alive longer.

Ford inhabits the role the way his character inhabits his well-worn jeans and t-shirt. He knows this guy. He has no illusions but he likes him and he makes us like him, too. Fraser, too often underrated as an actor, manages to make Crowley inspiring without making him unbelievable, especially in the scenes with the children and with Keri Russell as his wife. Jacobs’ script skirts the usual tensions. The Crowleys have some agonizing moments, but they never question their commitment to their children and each other. The children are played by Meredith Droeger, who has a nice dry humor, and Diego Velazquez, who has beautifully expressive eyes. Their healthy brother John Jr. (Sam M. Hall) has a lovely moment when he shows how devoted he is to helping his siblings. And Courtney B. Vance is as always most welcome as the father of two other children with Pompe, making a strong impression in his brief time on screen.

Because the tension is between the Crowleys and the disease and between Crowley and Stonehill and Crowley and the bureaucrats and money people, the story can present the family as functional in the face of the greatest possible tensions and terrors. In the past, we’ve seen Ford fight the Empire and the Nazis and Fraser take on mummies, but in this story they take on something even more scary and the result is touching and inspiring.