Puzzle: Kelly Macdonald strives to make things fit.

Why burn daylight snapping together a jigsaw puzzle when it’s easier (and more enlightening) to buy a ticket and watch two characters assemble one? The only missing piece to this otherwise easily fathomable romantic Puzzle is why Kelly Macdonald doesn’t get more starring roles.

Dusty, dirty, cheerless: three words to describe the birthday party preparations presented here at the outset, but Agnes (Macdonald) doesn’t seem to mind. Her entire universe revolves around her two sons, her jadrool of a husband (David Denman), and New Jersey. If that means stringing streamers, inflating balloons, and baking a cake, so be it. After all, what else does she have to do with her life? But there’s something odd about the way she carries the blazing-candled confection. Her head angled downward, as though not wanting to make eye-contact with the other celebrants, she sets the platter on the dining room table and pauses a moment before blowing out the candles. All you need to know about Agnes’ lot in life told in one concise, wordless preface. That’s how to introduce a character!

By way of manifesting her disconnect with technology, Agnes dangles a recently-gifted iPhone — aka “my alien robot friend” — as one would a dirty diaper. But two other baffling birthday presents in particular — one cosmic, the other wrapped — catch and hold her attention. Our somnambulistic homemaker was one piece shy of reassembling a serving plate she stopped in mid-party to Crazy Glue back together. Note that missing sliver! The economical presentation of first-time director Marc Turtletaub (best known for producing Little Miss Sunshine and Our Idiot Brother), combines with a more or less dependable screenplay by Oren Moverman (The Messenger, Rampart) and Polly Mann to assure audiences that everything will eventually come back into play.

For your correspondent, the colorful ten-piece Whitman tray puzzles that featured Looney Tunes or Hanna-Barbera characters were a childhood staple. They presented no challenge even to a five-year-old. After the third completion it went right in the garbage. There was a brief spike in my teens when a high school chum’s dad tried to give us something to do during the winter months. The all-white 500-piece puzzle, meant to pass the snowbound days, put a permanent end to the fascination.

Be sure to scribble, “To the person who has nothing” across the Hallmark card when giving the gift of jigsaw puzzles. That might have been Agnes’ initial reaction when removing the gift wrap, but a line from one of her earlier movies (Two Family House) holds just as much validity when applied in these parts: “We are all meant for something in particular.” As luck would have it, our mousy little Edith Bunker-ish wife and mother is a picture puzzle savant, twice completing a 1,000 piece puzzle in one sitting. And that was before she consulted the instruction sheet.

Puzzles soon become an addiction, as well as a means of avoidance and discovery. Knowing little of the outside world, Agnes leaves the safety of her neighborhood and hops a train to visit a game store in the heart of New York. It’s here that she spots an ad looking for a puzzle partner to compete in an upcoming jig-off.

Enter Robert (Irrfan Khan), a bulging-eyed millionaire eccentric who long ago lucked on an invention involving magnets that brought him millions. It also cost him a wife and puzzle partner; thus the ad. The actors play well off each other, even if the motivation for romance is a bit confounding. Robert’s attraction to Agnes is understandable, but it is hard to believe that she would risk losing her family over an affair with a bored game enthusiast, no matter how strong a physical attraction. Hubby Louie’s greatest sin is one of inattentiveness that borders on apathy. Short of turning a cliched good provider into a cliched abusive spouse, there’s not enough here to justify the affair.

Before unboxing Macdonald’s latest and spreading the irregularly cut pieces of pasteboard face up across the multiplex screen, it might behoove one to track down a copy of Raymond De Felitta’s aforementioned Two Family House, a similar-themed dramedy released almost two decades ago that featured the actress in a leading role. Puzzle is not an officially sanctioned sequel by any stretch of the imagination (other than my own). But if my findings are correct and one were to tack a fade-out to the end of TFH, add fade-in to the head of this film, and between the two wedge a “20 Years Later” title card, the transition would almost go unnoticed.