It’s only just that a year that’s already seen such wretched fish-out-of-water comedies as “New in Town” and “The Proposal” should close with another one. “Did You Hear About the Morgans?” may reunite writer-director Marc Lawrence and star Hugh Grant, who worked together on “Music and Lyrics,” but it’s not even up to the mediocre standard of that movie.

Grant plays Paul Morgan, a highly successful New York lawyer who’s been tossed out of his plush Manhattan apartment by his wife Meryl (Sarah Jessica Parker), an equally successful real estate broker, because of his extramarital fling. Desperate they should get back together, he arranges a dinner with her, but on the way back home they witness the murder of her latest client by a hit-man (Michael Kelly), who then targets them. The feds persuade the couple to go into the witness relocation program and fly them to a remote town in Wyoming where they become houseguests of grizzled Marshal Clay Wheeler (Sam Elliott) and his rifle-packing wife Emma (Mary Steenburgen).

What follows is foreordained. The culture clash is profound as our city slickers not only interact with locals like crusty diner-owner Earl Granger (Wilford Brimley, looking as though he’s barely ambulatory) and find the joys of shopping for bargains at the Big Barn but also have to deal with critters like brown bears and rodeo bulls. In the process, of course, they learn the charm of a land where everybody helps everybody else, even leaving trucks unlocked in case someone needs to borrow them, while rekindling their love for one another again. (The latter involves not only adopting a child but getting Meryl pregnant.)

Of course, there has to be a big finale in which the killer makes his way to Wyoming but gets stymied in his attempt to kill the Morgans by the locals. Getting there, to be sure, requires some pretty idiotic decisions on Meryl’s part (she decides to call her adoption agency, though warned not to) and on that of the Morgans’ relentlessly unfunny young go-fers Jackie (Elisabeth Moss) and Adam (Jesse Liebman), who decide to contact them while also falling in love. But intelligence is at best optional in the characters of movies like “Morgans.”

This is sheer by-the-numbers stuff, played sluggishly and without much charm. Grant does his customary flustered shtick, but this time around the throwaway “zingers” Lawrence puts in his mouth fall flat more often than not. Parker makes a colorless partner for him, but even the sprightliest actress couldn’t have pulled off the last-act revelation Meryl abruptly produces to steer the Morgans’ reconciliation off the rails. By contrast Elliott and Steenburgen are an amiable pair, though no less cliched than the Minnesota yokels in “New in Town.” The third couple, Moss and Liebman, are simply irritating.

“Morgans” is visually a bland picture, shot (in New Mexico as a stand-in for Wyoming) without panache by Florian Ballhaus, and it ambles along without much energy, the result not only of Lawrence’s prosaic direction but Susan E. Morse’s editing, which lets scenes run on long after their shelf life has expired. An annoyingly perky score by Theodore Shapiro, unfortunately, complements the action perfectly.

The result is a movie that might have been called “Witless Protection,” if that title hadn’t already been taken (damn you, Larry the Cable Guy!).