Even in the most dystopian societies, a free and accessible medical service is essential.

“Thank God the Doctor Is In” is an encouraging sign of change in Poland, where the lack of medical care is poorly understood and translated, and it will be seen by about a million people in a movie in which the man behind it is Polish-American writer-director Iwona Radomski. Radomski is best known for such films as “Waitress” and “Cold Water.” She wrote a book, Permata, that details how the rest of us can stop suffering from global poverty. Now she’s turned her attention to medicine, and the politics of healthcare in Poland.

The Hungarian-born, Polish-trained film critic and the film’s producer, Pawel Wojtaszek, were close friends who connected through a shared love of literature. The film is the opening-night film at this year’s Tribeca Film Festival, which begins on Thursday. The first-time screenplay by Radomski for a film starring John Hawkes, they wanted to tell the story of the two men who met when the younger doctor, Lasko, was in an Army field hospital in Afghanistan and hired the older doctor, Preosczalski, to be his interpreter, and prevent someone else from going on trial for treason.

Writer-director Iwona Radomski (right) with her star John Hawkes on the set of “Thank God the Doctor Is In.”

At the end of World War II, the two men were forced by the communist authorities to abandon their real jobs. Lasko, who was serving as the Army’s senior medic, received a government pension but had to settle for whatever jobs were available in a chain of neighboring hospitals. When the market was closed, it was impossible for him to work.

The story of the two men trying to communicate has a very touching quality. “I think a good part of the material we worked on was becoming friends,” Hawkes says.

One of the scenes that Radomski most wished to include when writing the script was when the men were reunited at the end of the war. But the “Thank God the Doctor Is In” shoot took place in central Poland, where the doctors (from Poland, Czechoslovakia and the Soviet Union) lived and had not seen each other for years.

Ewert Daus, the award-winning cinematographer who made the world of “House of Cards” feel like one intense home, shot the three-month shoot as accurately as he could, without the actors knowing that his film’s title would be so instantly recognizable. “Iwona has managed to go back and forth between artistic realism and historical accuracy,” says Daus.

Asked to characterize the film’s message, Radomski says that “you can’t help but feel that health is one of the last human rights, and I hope that everyone will think about it.”