"Tribalism" is a word that has become commonplace this year.
It's also the premise on which new feature-length domestic thriller Let Him Go is built.
Defined by the Oxford English Dictionary as "behaviour, attitudes, etc. that are based on supporting and being loyal to a tribe or other social group", the concept is as applicable to today's political landscape as it is to the characters and fam- ilies within the film.
"Who knew how confronted we would be by tribalism these days," says actress Diane Lane.
"We need to appreciate the good.
"This pandemic has brought out the best and the worst in people and, you know, we need to help each other and find common ground and cease and desist from making enemies."
Tribalism is, in essence, the key ingredient that makes Let Him Go so relevant to today's audiences.
Written and directed by Thomas Bezucha (Monte Carlo, The Family Stone), the adaptation of Larry Watson's novel sees Lane (55), who's best-known for her roles in Unfaithful and Justice League, star alongside Oscar winner and The Bodyguard actor Kevin Costner (65).
A plotline that combines classic Western elements with a darker undercurrent, the film, set in the depths of Montana, sees Costner take on the role of retired sheriff George Blackledge, with Lane stepping into the shoes of his wife, Margaret.
"It's kind of a road trip movie with a long-term relationship that's going through something very intense," Lane says.
"As Kevin Costner said, it's an honest movie, versus a fairytale. In some ways it's more European than Amer- ican.
"They want to heal their hearts from the loss of their son.
"At the same time, they're given this golden opportunity to have a quest to save their grandson, which is the ultimate homage to their deceased boy.
"So, you're dealing with a very poignant internal experience, but the external ex- perience that comes at them is more than they could ever prepare for in a way."
On a journey of hope, the couple set out to ensure the safety of their grandson after their widowed daughter-in-law remarries into a family with a murky reputation.
"Where the plot takes them eventually is almost a different movie, which I found very intriguing," Lane says.
"My character decides she's going to intervene on behalf of her grandson because she witnesses him experiencing violence at the hands of the new family he's living with.
"Watching them go through their ways of healing from grief and this road trip that they're on and where it leads, I just thought it was a page-turner.
"I knew it was a great script, so I had it sent to Kevin. I asked him to read it and, he's no dummy, he knows a great screenplay when he reads it.
"So when he said yes, I knew we were going to be in a good place."
At first glance, the film centres on the simple concept of family looking out for family.
However, it quickly becomes clear that love and protection are entirely subjective, as a straightforward reunion between the grandparents and their grandson appears increasingly out of reach.
"You've got three different mothers in this story and you see what makes a mother a good mother," Lane says. "And what does that mean? How is that interpreted?"
After the couple discover the whereabouts of their grandson, tensions rapidly rise as Margaret comes face to face with her new counterpart, Blanche Weboy.
Played by The Crown and Maleficent actress Lesley Manville, Blanche is a fiercely- protective grandmother who exhibits her own unique form of tough love.
"Lesley Manville is so riveting in this movie," Lane says.
"When you meet her character, and when George and Margaret walk into her home and meet her boys and her family, she lists her wounds.
"She announces that she's a survivor of this and this and this, and that's how she identifies herself.
"If that's not somebody telling you what you're in for, I don't know what is."
In a similar vein to tribalism, the film's title, Let Him Go, becomes applicable to mul- tiple characters as the story- line progresses.
"I loved the title Let Him Go because it's an instruction," Lane says.
"You sort of say, 'Is that God talking? Who's supposed to let somebody go?' It was almost like the end of a romance or something - you don't know what to expect.
"Everyone in there could be told to 'let him go' at one point, and yet no character says it, which I think is important.
"When you hear the title come out of somebody's mouth, you think, 'Oh, OK, well, we saw that coming'. But in this one there's a lot of things that you don't see coming and that's why I had respect for Tom's take on it."
It was yet another element that drew Lane to the project during the early stages of pre- production.
She admits, however, that she hadn't read the original book before filming, having been told "not to bother my pretty little head with things that we couldn't include, which happens sometimes".
Novels aside, it was Bezucha's work on The Family Stone that first convinced the actress that this was a role for her.
"I remember meeting him at the very elegant eatery that's attached to Lincoln Centre," she says.
"He was in a booth and I came walking over and it was interesting to see what people look like because, you know, when you're in front of the camera everyone knows what you look like.
"He has a real gift for all the different points of view that are happening within a scene, a story, even the genius of the title of our film and of the book that covers so many different perspectives.
"That's what gave me confidence that he was the right person for the job."