Charles Dickens gets the “Shakespeare in Love” treatment in the slight, but enjoyable, “The Man Who Invented Christmas.” “A Christmas Carol” it’s not, but it is about how that holiday classic came to be during a harried six-week write during fall 1843. The novel was a hit, of course. And it could not have come at a better time for the author, who was in the throes of a bank-breaking slump resulting from having written three straight flops. Or, that’s what the movie insinuates; all the better to fit its story-behind-the-story template in which Dickens’ own hardscrabble life mirrors the book’s recurring themes of poverty, charity and hope.

At times it’s a little too on the nose, like his servant’s penny dreadful providing the inspiration for the three ghosts; or, a visit from Dickens’ sickly nephew spawning the idea for Tiny Tim. And, naturally, there are the inevitable bouts of writer’s block and the breathless racing against the clock to get the manuscript in on time. But for the most part, it’s a fascinating exploration of the writing process, particularly how authors are receptacles for the words and deeds of the people around them, all filed away and ready to be sprung on the page whenever the situation warrants.

We see it occurring — perhaps too much — every time Dickens steps out from the large London brownstone he just bought but can no longer afford. And it intensifies upon the arrival of his well-meaning deadbeat father, John (the great Jonathan Pryce), whose irresponsibility in Charles’ youth ticketed the old man for debtors prison, and the son for a miserable stint inside the dreaded workhouse.

It’s a slight Charles can’t seem to reconcile — until he associates his love-hate feelings toward his father with the miserable, miserly Scrooge’s ability to eventually find his heart of gold. But John is but a piece of Scrooge. The real thing resides deep inside Charles’ mind and presents himself as an imaginary figure in the person of the great Christopher Plummer. One would think Dickens was going insane given his fanciful conversations with the surly old apparition, whose first words are none other than “ah, humbug.” Plummer is a delight in the role, but he’s not nearly mean enough. So the eventual thaw of Scrooge’s icy heart comes as no surprise. But you don’t really care. Plummer’s constant twinkle is too hard to resist. You actually crave more of him than director Bharat Nalluri (“Miss Pettigrew Lives for a Day”) allows. You also can’t help wishing that some aspiring filmmaker would cast Plummer in a more faithful version of “A Christmas Carol.” Just as delightful is “Downton Abbey” vet Dan Stevens as Dickens. Even though he plays the part a tad too beholding to Hugh Grant for my taste, he’s still makes Dickens an entertaining guy to be around. Stevens is a master of expressing both befuddlement and amazement, as Dickens demonstratively verbalizes his every emotion, often patting himself on the back like a sort of 19th century Donald Trump. It’s quite fun this self-absorption, and it goes a long way in pulling you through some of the more eye-rolling moments in Susan Coyne’s somewhat shallow adaptation of Les Standiford’s novel.

Purists will no doubt protest, but they’ll have to admit that this Dickens is a helluva lot more fun than the stodgy misanthrope Ralph Fiennes turned him into in the daunting “Invisible Woman” a couple years back. What Stevens’ performance lacks in edge is more than compensated by charm, a trait that filters down through an excellent supporting cast that includes Morfydd Clark as Dickens’ flustered, put-upon wife, Kate; and Anna Murphy as the family’s irresistibly adorable Irish nanny, Tara, the woman who Dickens regularly uses as a sounding board for his novel’s more daring ideas. Kudos, too, to Justin Edwards as Dickens’ best pal and literary agent John Forster, and a terrifically pompous Miles Jupp as famed London book critic William Makepeace Thackeray.

All fit nicely into the film’s requisite dank-and-dark London settings, captured evocatively by production designer Paki Smith, costumer Leonie Prendergast and cinematographer Ben Smithard. It’s all top-of-the-line work and done with great attention to detail. They set the mood and the excellent ensemble make it all sing — even when that mood borders on cornball.

And what about that title, “The Man Who Invented Christmas”? What does it mean? I’m not entirely sure, but title cards at the beginning and end of the movie suggest that before “A Christmas Carol,” the yuletide season was a minor nuisance. Or, as Scrooge would say, “a poor excuse to pick a man’s pocket every 25th of December.” But after the novel was published on Dec. 19, 1843, it’s said the holiday became a beacon for selflessness and generosity. Believe that if you will. It’s all very subjective. And even if you don’t buy in, it’s hard to argue with an invention as amiable as this.

“The Man Who Invented Christmas”
Cast: Dan Stevens, Christopher Plummer, Jonathan Pryce, Simon Callow and Morfydd Clark.
(PG for thematic elements and some mild language)
Grade: B