When you first hear the synopsis for THE SHAPE OF WATER, you might not believe that it’s a favourite to win the Oscar for Best Picture. The basic idea – lady falls in love with fish-monster – sounds utterly bonkers. But as he’s shown before, in films like PAN’S LABYRINTH and CRIMSON PEAK, director Guillermo Del Toro has a remarkable ability to turn the most bizarre premises into unconventional, yet breathtakingly charming fairytales.

Set during the Cold War, the story follows Elisa (Sally Hawkins), a mute janitor working at a government facility. Her only friends are her outspoken co-worker Zelda (Octavia Spencer) and Giles (Richard Jenkins), an elderly painter and closeted gay man. Del Toro has said that he wrote the movie as an “ointment” for modern society’s ills, and as you watch Zelda interpret for Elisa’s sign language at work, or Elisa accompanying Giles on ‘dates’ to the pie shop, your heart will indeed be warmed by such refreshing displays of loyalty and acceptance. These themes become yet more apparent when the facility brings in a mysterious creature. They want to torture him in the name of science, but Elisa gradually forms a spiritual (and yes, even romantic) connection with the “asset”.

The film feels joyously unashamed of how strange it is, as if to say, “If you don’t like me, then you’re in the wrong cinema.” The fish-man is never really explained, because he doesn’t need to be. The sets look really artificial in a fantastic way, like the sets of classic musicals or B-movies. Even the rules of genre are bravely ignored, right from an opening sequence that takes you through an eerie underwater apartment, with music reminiscent of AMÉLIE or LA LA LAND.

It’s all tied together by Del Toro’s typically wonderful direction, and by a brilliant cast. Spencer is great as always, as is Jenkins as the shy, sweet Giles. Michael Shannon puts in terrific work as Strickland, the arrogant, single-minded head of security, who opposes pretty much everything the film stands for. And then there’s Doug Jones, being typically amazing as the “Amphibian Man”, though he’s used more sparingly than you might expect.

But the shining star is obviously Hawkins. The believability of the tale rests largely on her shoulders, on her ability to sell this character without uttering a word. Luckily, Hawkins has one of the most expressive faces in the industry. She puts such emotion into her signing that a few days later, when you think back to watching her, you’ll swear you can remember the lines in her voice.

One of the standout moments, where the acting, direction and writing all come together beautifully, is when Elisa argues with Giles over whether to save the creature. Giles points out that she’s still signing “thing” rather than “person”. She explains, compassionately and powerfully, why she empathises with him; when the Amphibian Man looks at her, he doesn’t know how she is “incomplete”, he simply sees her for who she is. It’s probably the only scene that actively tries to convince you to take this story seriously. To believe that a woman can fall in love with a fish-man. And actually, it’s all the convincing you’ll need.