Kenneth Branagh’s “All Is True,” a heavily fictionalized biopic about William Shakespeare that focuses on his return to Stratford after his retirement, is the lifeless story of a man who gets to realize Jean-Pierre Melville’s greatest ambition: To become immortal, and then die. By the time this curious but inert character sketch of a movie begins, Shakespeare is already halfway there.

Convincingly embodied by Branagh, who squeezes his head under a prosthetic hairline in order to bring his lifelong obsession with the Bard to its logical conclusion, the poet and playwright is first seen as the Globe Theatre burns to the ground behind him, his livelihood going up in flames. A stage cannon has misfired during the debut performance of “Henry VIII” (also known as “All Is True”), sparking a blaze that ends Shakespeare’s career and sends the overachieving scribbler back to his wife and daughters to explain what (and who) he’s been doing all this time in London. As the smoke clears, he’s forced to reckon with the fact that the scope of his writing dwarfs the smallness of his life, and that work is only part of what constitutes a legacy. A legend in his time, but a ghost in his home — think of him as a Disney Dad in a well-laced doublet — Shakespeare returns to Stratford in order to fill the void he’s left behind.

To hear it from Branagh and screenwriter Ben Elton, Shakespeare spent the last three years of his life trapped in a series of dour Malickian sunsets and increasingly skewed dutch angles as he struggled to pen the last act of his life story; if you’ve ever wanted to see William Shakespeare run his hand through a wheat field and deal with his horndog son-in-law’s wandering libido, this is the movie for you. For you, and very few others. More than anything, “All Is True” feels like a film that Branagh needed to make for himself as a palate-cleanser between mega-budget Agatha Christie adaptations. It’s 105 minutes of watching someone clear his throat, although Branagh’s remarkable cast (himself included) occasionally make the experience a bit more rewarding than it sounds.

There isn’t a plot so much as a series of terse encounters. Many scenes find Shakespeare bickering with his illiterate wife Anne (a stern and owlish Judi Dench, giving one of her most Judi Dench performances to date), who finds that spending time with her errant husband and tracing his many foibles is the best medicine for her lifelong feelings of inadequacy. He also tries to reacquaint himself with his two adult daughters, Judith (Kathryn Wilder) and Susanna (Lydia Wilson), neither of whom are all that psyched that daddy has come home from a decades-long business trip without any souvenirs.

Most of all, Shakespeare tends to the sad little garden outside of the family house (played by a 15th century Tudor Manor near Windsor Castle), a barren plot that he sees as a tribute to his late son Hamnet (Sam Ellis), who died as a child while the Bard was off in the big city. Playing off the boy’s name in a way that many will notice but few will enjoy, “All Is True” flips the script on “Hamlet” to find the the child haunting his father, as Hamnet returns from the dead in a handful of scenes too numb and clumsy to convey a great writer’s grief. It’s one thing to suggest that Shakespeare was frustrated by the struggle to make his family seem worthy of the fiction he wrote in their stead, it’s another to saddle him with expository dialogue like: “I’ve lived so long in imaginary worlds, I think I’ve lost sight of what is real.”

No, the movie is not told in iambic pentameter, nor is it thoroughly modernized in a bald appeal to modern audiences. On the contrary, Elton stakes out some clever middle ground, opting for language that sounds like a more social version of the vernacular that Shakespeare would use in his plays. There’s no risk of misunderstanding the extent to which the great poet has ignored the women in his life and what they may have wanted for themselves; his relationship with Judith, Hamnet’s twin, is particularly fraught, and Wilder’s performance is brilliant for how she plays love and contempt as two notes in the same dissonant chord.

Likewise, anyone who hasn’t been lulled to sleep by the film’s lethargic first act will be able to register what’s at stake when the Earl of Southampton (Ian McKellan, in a memorable cameo) rides through Stratford in order to pay his respects. The subject of several love sonnets that Anne doesn’t know how to read, the Earl represents the high status that even a commoner of Shakespeare’s talent could never hope to reach, and the unrequited love that forced the poet retreat to his family.

Was the playwright really in love with another man? It’s hardly the most controversial Shakespearean rumor — the Anti-Stratfordians don’t even think Shakespeare authored his own plays. But “All Is True,” a self-serious movie that was titled with tongue in cheek (and often feels as though it’s clenching its jaw to keep from laughing at itself), is no more interested in the facts of Shakespeare’s life than Shakespeare was in the facts of the lives he wrote about. For Branagh, his idol is a means to an end; a too-convenient shorthand for all the Great Men who weren’t as good as they seemed.

It’s a strangely familiar approach to a story about a peerless figure, and all the stranger considering that Shakespeare — it seems — lived to appreciate the magnitude of his accomplishments. Bards, they’re just like us! From start to finish, the film shares in its protagonist’s struggle to reconcile the planetary sweep of his genius with the personal nature of its consequences, and Branagh’s performance, though always compelling, never lands on a legible balance between “immortal talent” and “devoted family man.” Both in front of and behind the camera, he makes the transition from one side of Shakespeare to the other with all the grace you might expect of a movie that combines the pace of “A Quiet Passion” with the ham(net)-fisted patriarchal redemption of “Steve Jobs.” The result is a portrait that’s equally sullen and playful, clever and confused; for all its pleasures, “All Is True” never amounts to the sum of all the many parts that Shakespeare may have played in his time or thereafter.