PORTLAND, Maine (AP) — Most Maine schoolchildren know about the boy lost for more than a week in 1939 after climbing the state’s tallest mountain. Now the rest of the U.S. is getting in on the story.

Opening in 650 movie theaters on Friday, “Lost on a Mountain in Maine” tells the harrowing tale of 12-year-old Donn Fendler, who spent nine days on Mount Katahdin and the surrounding wilderness before being rescued. The gripping story of survival commanded the nation’s attention in the days before World War II and the boy’s grit earned an award from the president.

For decades, Fendler and Joseph B. Egan’s book, published the same year as the rescue, has been required reading in many Maine classrooms, like third-grade teacher Kimberly Nielsen’s.

“I love that the overarching theme is that Donn never gave up. He just never quits. He goes and goes,” said Nielsen, a teacher at Crooked River Elementary School in Casco, who also read the book multiple times with her own kids.

Separated from his hiking group in bad weather atop Mount Katahdin, Fendler used techniques learned as a Boy Scout to survive. He made his way through the woods to the east branch of the Penobscot River, where he was found more than 30 miles (48 kilometers) from where he started. Bruised and cut, starved and without pants or shoes, he survived nine days by eating berries and lost 15 pounds (7 kilograms).

The boy’s peril sparked a massive search and was the focus of newspaper headlines and nightly radio broadcasts. Hundreds of volunteers streamed into the region to help.

The movie builds on the children’s book, as told by Fendler to Egan, by drawing upon additional interviews and archival footage to reinforce the importance of family, faith and community during difficult times, director Andrew Boodhoo Kightlinger said.

“Times are dark in the country in a weird way. You know, there are political divisions, society is a little on edge, and everything. And I thought, here’s a movie that reminds people about just the power of community, the power of caring about your neighbors. And the themes were so basic and simple. And for some reason, we just sometimes seem to be reminded of those things,” he said.

The movie brings a vintage vibe to the big screen.

Filming took place in the woods of upstate New York, with the crew battling insects and wading through shoulder-height water for scenes in a canoe. Other scenes were filmed on Mount Katahdin and a replica mountaintop built in a soundstage, complete with lichen-covered granite stones, blowing wind and rain and lightning.

The movie gives the perspective of the distraught family as well as the terrified boy, played by Luke David Blumm. His father is played by Paul Sparks (“House of Cards,” “Boardwalk Empire”). Maine native Caitlin FitzGerald (“Masters of Sex,” “Succession”), who read the book and met Fendler as a girl, takes on the role of Donn’s mom.

FitzGerald isn’t the only Mainer involved in the film. A producer Ryan Cook, who also grew up in Maine, partnered with another Mainer, Dick Boyce. Both were familiar with the book and Cook became close to Fendler and previously produced a documentary about him.

Sylvester Stallone’s Balboa Productions took on the project because he liked the story of the plucky underdog.

Kightlinger, who hiked Katahdin to audition for the job of directing the movie, said adventure stories are a dime a dozen. This one, he feels, was made stronger by the backstory of the difficulties Donn and his father had connecting.

“It’s ultimately about a kid who just wants a hug from his dad,” Kightlinger said. “That’s such a pure, simple message, and I think more movies should aspire to just do that and remind people of the simple things, because there’s a lot of noise in our world now, and the simple things sometimes get lost.”

Nielsen said the story is both riveting and practical. In her classroom, the book inspires discussions about geography, plants and wildlife; preparation and survival skills; and resilience in the face of adversity.

Her teenage son learned a valuable from the book: Stay together in the wilderness.

The 16-year-old was hiking Mount Katahdin with friends a few weeks ago. After hiking above the trees, they were traversing rocks when a storm came in. The three made the difficult decision as a group to turn back.