“Mending the Line” is a simple, sentimental story of combat veterans bonding and healing the wounds of war via fly fishing in Montana.

A fine cast doesn’t turn this into any sort of existential epic, as it doesn’t transcend any of the genres it mashes up. No, it isn’t “A River Runs Through It.”

But the the PTSD is treated realisticially and with sympathy. And the metaphors for fishing and life, the appreciation of fly fishing as a subject for some of the most sensory and soulful sports literature and meditative moments on the stream lift it and make it worth your while.

A prologue tells us how Marine John Colter (Sinqua Walls) came to be in a VA hospital in Montana, healing his broken bones and torn skin, but crawling into a bottle to cope with the survivor’s guilt over the fateful command decision he came to make and lives altered by it.

His doctor (Patricia Heaton) hears his hopes of “going back home,” to the Corps, “the only real family I’ve ever had.” And she sees how little good group therapy is doing him.

As she’s got this cranky old Vietnam War vet (Brian Cox) who won’t heed her advice about not going fishing alone thanks to his advanced years and shaky health, she takes a shot at solving both her problems.

Colter is sent to see Old Man Ike about learning to fish.

Ike Fletcher’s regular fishing buddy is just as timeworn. And if you didn’t think you needed to see the star of “Succession” swapping jibes and casts with Oscar winner Wes Studi, you haven’t been thinking hard enough. Their scenes are a little underwritten, but they don’t need a lot of help creating crusty but sweet chemistry.

Perry Mattfield plays Lucy, a sad-eyed local librarian who occasionally goes to the VA hospital to read to the veterans. When Ike puts Colter to work cleaning the back room at the local flyfishing shop, he not only chides him with “There’s tactical training and there’s boot camp. THIS is boot camp.” He assigns his reluctant pupil reading.

“There’s more great literature written about fly fishing than any other sport.” That’s how Colter meets Lucy and discovers books like “Casting Forward.”

“There’s a great deal about living that trout can teach us.”

There’s not a lot to this picture, even though our three leads harbor “secrets” and even though not all problems can be solved by “healing on the water,” learning how to properly cast. The pacing is a bit slack, as well.

But Walls lets us feel the pain of his injuries and his imagined guilt, Cox uses his new student to try and find one last “recon” mission and Mattfield lets us ponder her “secret” and the ways it has taken away her spirit and being trapped in this town and human reminders of this tragedy is killing her spirit.

And the patience of the sport and the tranquility of the settings casts a spell, and it all comes together in modestly, honestly moving ways.

Rating: R (Language|Some Violent Images)

Cast: Sinqua Walls, Brian Cox, Patricia Heaton, Perry Mattfield and Wes Studi

Credits: Directed by Joshua Caldwell, scripted by Stephen Camelio. A Blue Fox release.

Running time: 2:02