In “Let Him Go,” Kevin Costner and Diane Lane play a longtime married midwestern couple in the 1950s who attempt to save their grandson and dead son’s widow from the violent family she married into.

Costner insists viewers will be in for the same kind of ride they enjoyed with a couple of his classics.

“I try to become [the moviegoer] when I’m reading the script for the first time, which is, what’s this journey going to be for somebody, and too often the scripts don’t live up to it,” the actor told Variety while promoting “Let Him Go.” “But once and awhile they come along. I’ve had those in my career, the ‘Field of Dreams’ and the ‘Bull Durham’s.’ I could go on and I’ve been lucky about that and this script really understood its edge. It kept its promise ’till the end because that’s the only place it could go.”

It’s Lane’s character who convinces her retired sheriff husband that they must do everything they can to rescue their grandson from a family of thugs ruled with an iron fist (and fire-engine red lipstick and a cigarette) by Blanche Weboy (played by Lesley Manville).

“Ask most men who have been in a long-term marriage how it works,” Lane said. “I’m kidding but I’m not. ‘Happy wife, happy life’ is a saying for a reason I’m sure. All joking aside, these people are processing grief and this is her process.”

Manville said there wasn’t much to like about her character — but that’s a good thing because they woman is evil. “It’s her riles and nobody is going to veer her away from them and she’s absolutely the mistress of her own world,” she said. “There’s not an awful much I like about her except I absolutely loved playing her. I think on a normal day, you wouldn’t think, ‘Let’s get a bad North Dakota mama in the 1950s — oh, I know, Lesley Manville!”

“Let Him Go” is in theaters on Friday.