John Steinbeck, who crisscrossed the country with his standard poodle and lived to write the tale (Travels with Charley), noted that "I've seen a look in dogs' eyes, a quickly vanishing look of amazed contempt, and I am convinced that basically dogs think humans are nuts."

That nuttiness - albeit safely couched in middle-age and upper-middle class comforts - is on display in Lawrence Kasdan's Darling Companion, a shambling and not exactly deep ensemble piece centered on a long-married couple (Diane Keaton, Kevin Kline) and the dog that comes into, and then out of, their lives.

Kline is Joseph Winter, a Denver surgeon with a thriving practice and an inability to put his work - and his ego, and his cellphone - aside. Keaton is Beth, his long-suffering, but also long-loving wife. They have a grown daughter, Grace (Elisabeth Moss). The nest is empty, and maybe the marriage is a little empty, too.

One day, Beth and Grace are driving, and Beth spies a huddle of fur and paws, off in the bushes by the shoulder of the road. Next thing you know, the Winters - over Joseph's protestations - have a new family member: Freeway. And that's not all - Grace, who's never had much luck with boyfriends, may have found one in the veterinarian, Sam (Jay Ali), who examines the dog.

And so Beth has someone to walk with, to lock eyes with, to amuse her while her husband is operating on slipped disks and sciatic nerves.

And then Joseph loses Freeway, on a run in the woods, by their big cabin in the Rockies. They are there to celebrate their daughter's engagement (yes, to Sam). Joseph's wacky sister, Penny (Dianne Wiest) is in attendance, with her tactless new beau (Richard Jenkins), and Penny's son, Bryan (Mark Duplass), who is Joseph's partner in the practice. And then there is the exotic Carmen (Ayelet Zurer), the Winters' caretaker. She's got a bit of the gypsy about her, and she has "visions" of where Freeway may have gone.

Family. Friends. Lovers. Dogs. It's a recipe for conflict, for liquor-catalyzed confessions, for honesty and hypocrisy - and for angst and tears, as Freeway stays missing, and missing, and missing some more.

It's fun to watch Keaton and Kline together, bickering and (of course) bonding all over again. They deem Jenkins' Russell an unworthy partner for Penny at first, but (of course) he proves himself otherwise. And how can Bryan not fall for Carmen and her strange, seductive ways?

Kasdan - who enjoys throwing large numbers of friends, family, and whole communities together (The Big Chill, Grand Canyon, Mumford) - lets his actors go about their work in a loose, improvisatory manner. No heavy lifting here, but everyone seems up for it. And up for yelling "Freeway!" loudly, and worriedly, into the trees.EndText