A still from the movie “Island Zero.”

Laila Robins, left, stars in the movie “Island Zero.”

Even best-selling Maine author Tess Gerritsen needed someone to tone back on some of her grandiose plans during preproduction and filming on her low-budget horror film “Island Zero.”

Being forced to make quick edits and come up with new ways to tell the story was easy for someone who has sold more than 30 million books. 

“Tess would want to do stuff that we couldn’t afford or would have been very tricky,” producer Mariah Klapatch said. “I’d have to be like, ‘this isn’t going to work. What can we do?’ The amazing thing about Tess is that she kind of says, ‘Alright, we’ll get rid of that.’ And she would come up with five new ideas right away.”

A former physician, Gerritsen is the author of more than two dozen suspense and medical thrillers. The TNT series “Rizzoli and Isles” is based on a series of her books about a Boston detective and medical examiner.

Gerritsen, though, is a lover of horror films, growing up watching the horror classic of the 1950s.

“Tess has a dark, twisted sense of humor,” Klapatch said. “She loves horror, and she loves the old monster movies.”

A family project, Gerritsen wrote the screenplay for “Island Zero” and her son, Josh Gerritsen, a professional photographer, served as director. Klapatch, a childhood friend of Josh Gerritsen in Camden, eagerly came on board, bringing experience as a sound mixer and producer in Los Angeles and New York making commercials and videos. 

“Island Zero” tells the story of what happens to the residents on an isolated Maine island when the ferry, the lifeblood of the island, stops coming. The power goes out and communication with the mainland is lost. Boats that leave the island never return.

The Gerritsens originally wanted to base the story on a farm with the animals turning into monsters, but when Klapatch described the difficulties of filming that with their $400,000 budget, they switched the locale following a trip to Monhegan Island, an island 12 miles off the Maine coast which allows no cars. 

“What would it be like to live in a community that (is) isolated and is so limited by one mode of transportation?” Klapatch said. “So what happens if the ferry doesn’t come?”

The film stars Laila Robins, a veteran actress who played Steve Martin’s wife in “Planes, Trains & Automobiles” and has a recurring role as the ambassador on the Showtime series “Homeland.”

Much of the filming took place in March 2016 in Camden, Rockport and Islesboro with a mostly Maine crew. Klapatch loved the experience of shooting in Maine.

“Most of my experience is shooting in New York and Los Angeles,” Klapatch said. “The challenge of shooting in a place like that is most people don’t really want you around. Stuff is expensive. Getting permits is a huge pain.

“The nice thing about shooting in Maine was all that disappeared because everyone was real excited to have us,” she said. “Permits are super laid back for the most part, and there is a lot of accessibility you don’t get in a bigger cities.”

The film received a five out of five stars by a Los Angeles film reviewer who saw it recently at a Boston film festival.

The showing at the Emerge Film Festival will be the film’s Maine premiere. Klapatch is hoping to find a distributor to bring the film to theaters by the end of the year.

Klapatch said a previous commitment will likely prevent Tess Gerritsen from attending the festival, but she expects several members of the cast and crew to be at the screening.