Welcome to the Rileys

Stewart? As usual, she’s just there, but I can’t think of another young actress who makes her there-ness work so well. All three actors come at this gloomy, borderline-preposterous tale from different directions; that they meet up at all — and they do — is a tribute to sincerity and craft.

It’s a little harder for the audience. The story line invites such horselaughs that writer Ken Hixon and director Jake Scott handle it too gingerly, as if at the end of tongs. Gandolfini plays Doug Riley, an easygoing Indiana plumbing-supplies wholesaler whose marriage and life have drifted after the death of his teenage daughter in a car accident. His wife, Lois (Leo), has a simpler approach to grief: She hasn’t left the house in years.

The unexpected death of a waitress (Eisa Davis) with whom Doug was carrying on a casual affair sends him into a spiral; during a plumbing convention in New Orleans, he goes AWOL and into the orbit of Mallory (Stewart), a teen-runaway stripper with a mouth like a toilet and post-Katrina living arrangements that are like the toilet’s toilet.

Doug’s not interested in what Mallory’s selling; to her considerable confusion, he checks out of his hotel with the aim of fixing up her house and life. The early scenes between the two are awfully queasy, and they aren’t helped by Gandolfini’s come-and-go Southern accent. When Lois decides she has to see what her wayward husband is up to, though, “Welcome to the Rileys’’ takes on a peculiar and gentle charm. Watching Leo convey the character’s wonderment as she solves the puzzle of driving a car for the first time in a decade is very special indeed.

The director’s the son of Ridley Scott (“Alien,’’ “Gladiator’’), and it’s as if he had consciously set up camp far from dad’s turf. “Rileys’’ is slow and observant rather than slick and propulsive; it waits for the actors to bring it home rather than dazzling us with style. While there’s much to be said for that, real is one thing and forceful another, and the movie’s discreet humanism too often stays on the page.

Gandolfini and Leo still convince us there’s a genuine marriage there, with genuine affection underpinning it, and Stewart somehow builds a character out of her patented mix of shrugs and sullenness. The movie deglamorizes both Mallory and the actress playing her; by the final scenes, the character’s very much the raw adolescent the other two mistakenly see as a replacement daughter. As a whole, though, “Welcome to the Rileys’’ tiptoes around its emotions without ever committing to them. You’re glad it’s not “Tony and Bella’s Big Adventure’’ even as you suspect that might have been a lot more fun.

Ty Burr can be reached at tburr@globe.com. For more on movies, go to www.boston.com/movienation.