From the first, the film cleaves to the viewpoint of linguist Louise Banks (Amy Adams), who loses her daughter to a lingering illness. When twelve alien ships appear, hovering above what appear to be random locations (including Devon, disappointingly never shown), Villeneuve focuses on their unsettling effect on human society; it isn't until Louise is recruited by Colonel Weber (Forest Whitaker) that we see one of the ships clearly for the first time, in a terrific swooping shot that contrasts its serene black crescent with the busy muddle of the army base hastily thrown up close by. It's a wonderful payoff to a long, careful build-up, with the menacing serenity of the floating ship enhanced by Jóhann Jóhannsson's brooding score.
Each ship opens a hatch at its base every 18 hours, to admit human representatives into a gravity-bending space where a pair of aliens appear behind a huge glass wall. The Russians and Chinese believe that fragmentary translations suggest the aliens are bent on conquest; as some kind of conflict appears inevitable, Louise and physicist Ian Donnelly (Jeremy Renner) scramble to decode the complex graphics the aliens blurt out in inky smoke, and parse their true meaning. Amy develops a relationship with the two aliens after shucking her protective suit; her and Donnelly's collaborative work on their cyphers is intercut with fragmentary glimpses of the life of her lost daughter; pace the Sapir-Whorf hypothesis, which posits that language alters the way we think, she slowly comes to see the world, and time, as the aliens do, a revelation that's the crux of the narrative's intricate double knot.
Villeneuve takes the science fictional ideas and the intellectual labour of attempting to understand the unknowable with admirable seriousness. Despite the ticking clock of threatened war against the aliens, and an undercooked subplot involving sabotage in the second act, the narrative unfolds at a deliberate, sombre pace, but amidst the exchanges of jargon and computer manipulations Amy Adams's performance, intense and vulnerable, maintains a focus on the emotional and personal consequences of understanding the aliens.