On a day, much like any other day, 12 huge (they're 1,500 feet tall) spaceships arrive at seemingly random points around the Earth. They hover just off the ground. Every 18 hours or so, a door opens in the bottom of each ship allowing humans to enter, if they wish.
Amy Adams plays world-famous translation expert, Dr. Louise Banks. Several days after arrival, the army comes knocking. Colonel Weber (Forest Whitaker) plays for her a 20 second tape of weird noises. Translate that, Weber says. Dr. Banks explains that it's impossible. A few days later she's taken to Montana, where the only ship to land in the US is hovering. By the way, she's great in this.
The aliens are very large octopus looking creatures but since they only have seven limbs we call them heptapods. We can only attempt to communicate with them through a transparent window. The creatures are embraced in fog. Although recordings have been made of the alien's noises at all 12 sites, no one has had a breakthrough. Dr. Banks, has a different idea, trying to use written language. She gets a written response instantly, which looks like this.
Not very obvious but a start.
I love science fiction, written and filmed. Most movie science fiction is of the spaceship shoot 'em style which I'll watch ("Star Wars: Rogue One" is out in a few weeks) but this is different. No human-alien fight scenes. This is not "Independence Day".
"What is your purpose in coming here?" is the question everybody wants Dr. Banks to ask. She eventually does but it takes most of the movie. The movie is largely her trying to understand the aliens language with a lot of background tension going on. The Chinese and Russians are also 'talking' to the aliens but when they understand the aliens to say "we are out of time", they jump to conclusions which heighten tension and cause the various teams to cut communication with each other.
Jeremy Renner plays physicist Ian Donnelly. He's solid but doesn't have much to do other than support Amy Adams. Forrest Whitaker as Colonel Weber does a good job as the straight-forward Army man trying to follow orders while trying to understand Dr. Bank's work. He does a good job not sinking into a cliche.
It is a pretty good movie. I might not take my young children to see it. Not because it's scary (although it is in parts, but more like international tension scary, which I'm guessing your average 8-year-old wouldn't understand) but because kids will find this boring. You might as well, there's not a lot of action. Amy Adams drawing alien symbols on graph paper may not be your definition of excitement. All though the movie Dr. Banks has flashes of memories of her dead daughter. The ending brings that story line and the aliens together through the use of great twist (which would be a major spoiler so you won't hear it here) making for a very satisfactory ending.