Thanks to the venerable Brattle Theatre, you might have recently revisited a handful of Tom Hanks’ early roles during the Harvard Square repertory house’s perfectly titled ’Hanksgiving. Among the many highlights was director Ron Howard’s 1984 comedic gem Splash. A romantic fantasy involving a lovelorn man who falls for the mermaid who saves him from drowning, it’s also a caper involving their flight from a government that regards this beautiful creature as something subhuman. Naturally, both the audience and Hanks’ hero know better.

Mexican filmmaker Guillermo del Toro doesn’t have Howard’s two Oscars, but the writer/director of Pan’s Labyrinth shares Howard’s affinity for science fiction and fantasy, which is on display in del Toro’s latest, The Shape of Water. This 1962-set tale flips the script on Splash by focusing on a human heroine who falls for her amphibian prince, a finned merman.

Ah, but this adult fairy tale isn’t a comedy, as there are sudden splashes of blood that occasionally add crimson to the film’s aquatic blue and green color palette, along with flashes of flesh that accentuate the fact that we aren’t in Disney territory either.

British actress Sally Hawkins has proven herself quite talented at burying her accent, though there’s little need to disguise it here as Elisa Esposito. The Cinderella-like cleaning woman that Hawkins wonderfully inhabits is a mute, silently mopping the floors and toilets of the bunker-like government research facility in Baltimore that employs her. This is quite the change from Hanks’ motormouthed funnyman in Splash, so to offset the dialogue deficit, Elisa works alongside the chatty Zelda Fuller (Octavia Spencer), who acts as her mouthpiece, translating her sign language as the plot requires.

Another friendship occupies Elisa’s time when she’s not working her overnight shift, this one with her neighbor, Giles. Heartbreakingly played by Richard Jenkins, this freelance illustrator, closeted gay bachelor and lover of old Hollywood musicals also doubles as the film’s narrator, waxing on about “the princess without voice” and a “tale of love and loss and the monster that tried to destroy it all” during the storybook voice-over that bookends the film.

But it’s images rather than words that introduce us to Elisa and her daily routine, which finds her waking at dusk, running a bath, turning on her stove and masturbating in the shallow water of the tub during the time it takes to boil a few eggs. It’s these eggs that she offers up as a tasty olive branch to the new (mer)man in her life, after he’s wheeled into the secretive labs inside a coffin-like tank that sparks her curiosity.

Drawn to a porthole on the tank’s exterior, Elisa peers through the murky water, silently placing her delicate hand against the glass, a gesture that goes unnoticed by Dr. Robert Hoffstetler (Michael Stuhlbarg), a marine biologist tasked with studying the creature’s water-breathing lung structure. But when her attention awakens the submerged “asset,” Richard Strickland (Michael Shannon) comes charging with the cattle-prod that helped him catch his gilled prey in the rivers of the South American jungle, where the amphibious anomaly was worshipped as a god by the locals. Even without his sadistic baton, you’d know this racist, sexist G-man was the embodiment of moral rot. Not the subtlest filmmaker, del Toro continually reminds us of this rot after two of Strickland’s fingers are bitten off, then surgically reattached, only to ooze pus and blacken as the tale grows darker.

Still, there are light moments to be had before the movie wades all the way into cross-species carnality, including the seated tap dance that Elisa and Giles engage in—inspired by Shirley Temple and Bill “Bojangles” Robinson in The Little Colonel—as well as a black-and-white production number straight out of the MGM musicals of the 1940s, merged with the fluid camera work of Stanley Donen’s ’50s-era films like Singin’ in the Rain. After all, it doesn’t get more ridiculous than watching a woman dance a waltz with a merman.

But for all of this whimsy, del Toro’s storytelling remains the weakest part of his repertoire. Hobbled by elaborate camera moves that are showy and self-conscious—though still attractively lit by cinematographer Dan Laustsen—he and co-writer Vanessa Taylor have created a heavy-handed and predictable fable involving three marginalized people who are rendered invisible for different reasons. One because of her disability, one because of her race and one as a result of his sexual orientation—a commonality that aids their goal to free the equally mute merman.

It’s just a shame that the literal fish-out-of-water they’re liberating doesn’t move beyond being an elaborate special effect. Buried underneath all of the prosthetics is a fine actor, Doug Jones, who’s been performing as various creatures in del Toro’s films for two decades. But no matter how insistently composer Alexandre Desplat borrows from Yann Tiersen’s Amélie score, neither his twee accordion cues nor del Toro’s overcooked direction can compensate for a shallow character that should have made a bigger splash. ◆

The Shape of Water ★★ 1/2

Starring Sally Hawkins, Doug Jones, Octavia Spencer, Richard Jenkins, Michael Stuhlbarg, David Hewlett, Nick Searcy, Stewart Arnott, Nigel Bennett, Morgan Kelly, Allegra Fulton, Lauren Lee Smith, Madison Ferguson, Jayden Greig and Michael Shannon. Written by Guillermo del Toro and Vanessa Taylor, based on a story by del Toro. Directed by del Toro. At Boston Common, Coolidge Corner, Kendall Square and in the suburbs.