“Megan Leavey” is not the kind of dog movie like Timmy is in the well and can’t get out, as in “What’s wrong, Lassie? Is Timmy in trouble?”

It’s the kind of dog movie where our heroine is trapped in a town so boring it might as well be a well. We came knowing that a dog will change her life and we keep watching the streets for him to appear.

Faced with a dull life in a duller town, Megan lives with her hard-as-nails, chain-smoking and Bud-drinking mother (a still sharp-as-ever Edie Falco) who only relates to people as clueless as she. Her mom is divorced from her last hubby (Bradley Whitford) because she slept with his best friend — who is now her employee of the month and new hubby — Jim (Will Patton in a Will Patton role.)

So Megan joins the Marines. Well, wouldn’t you?

Even in the Marines she keeps messing up and is assigned to clean out the kennels of the war dogs, where she discovers her real purpose in life, training and fighting in Iraq with her troubled dog Rex.

This is where the war stuff comes in, and it’s surely needed.

Megan has now found her true place in life with Rex, who clearly has found his, and before long, they’re tracking down buried bombs and getting caught up in a tight spot, where she, Rex and her squad are ambushed and wounded. (Wasn’t there a movie once called “Rex the Wonder Dog?”)

This is where the real story of Megan begins, as she figures out who she is, how she got into this life, and where she’s going.

Director Gabriela Cowperthwaite gives us just enough time with Megan’s family to convince us that risking death with a dog in Iraq is a smarter choice for Megan.

There is true life romance here with fellow Marine Matt Morales (Ramon Rodriguez) who is as pretty and nice as Megan. In fact, all of her fellow Marines are nice guys, including her tough drill chief. (I think that Common has found himself a career.)

For those of you old enough to remember the sibling rivalry of stars Olivia de Havilland and Joan Fontaine, I’m wondering how long before Kate and her sister, Oscar-nominated Rooney Mara, stay happy as their careers progress.

As for this critic, having seen both work now, I can say that Kate has the right stuff to do some serious work before she’s through. Rooney had a good chance to show her stuff in “The Girl with the Dragon Tattoo,” but fell short because she had to deal with the specter of Noomi Rapace — a hard task.

Director Cowperthwaite, who’s best known for her series of Iraqi desert warfare documentaries, uses her skills and plentiful combat experience well, and handles the in-your-face time with real actors well.

“Megan Leavey” is for the most part an engaging movie of the week “girl and her dog” movie that will bring tears to the eyes and tugs to the heart of dog loving audiences.

I must say it was good to see Falco and Whitford working again, even as a backup team for a girl and her dog. Both did well.

J.P. Devine is a former film and screen actor.