The film begins with the voice of Doctor Louise Banks (Amy Adams) . . . . .

Louise: [narrating] I used to think this was the beginning of your story. Memory is a strange thing. It doesn't work like I thought it did. We are so bound by time. By its order.

We see moments of Louise with her daughter, Hannah, from her birth . . . . .

Louise: It's okay. Come back to me. Come back to me.

Through Hannah's childhood years . . . . .

Hannah: Stick 'em up!

Louise: Are you the sheriff in this here town? My tickle guns are gonna get you! You want me to chase you? You better run.

Louise: [narrating] I remember moments in the middle.

Hannah: I love you. . . . . I hate you!

And up until Hannah's death at a young age from a fatal disease.

Louise: [narrating] And this was the end.

Louise: Come back to me. Baby, come back to me. [sobbing]

Louise: [narrating] But now I'm not so sure I believe in beginnings and endings. There are days that define your story beyond your life. Like the day they arrived.

Louise is a linguist and language professor. She's on her way to class when she notices several students clamoring around the school lounge television, focused on the news, but she walks on by. Louise begins her lecture, quickly noticing very few students are present.

Louise: Good Morning. Where is everyone? Okay. Well, let's get started. Today, we're talking about Portuguese and why it sounds so different from the other Romance languages. The story of Portuguese begins in the kingdom of Galicia. In the Middle Ages, where a language was seen as an expression of art.

She is interrupted by the students' cellphones chiming.

Louise: Any news you want to share?

Student: Doctor Banks, can you turn the TV to the news channel?

Various TV Anchors: . . . but, police have already set up a blockade around the area. As you can see, we've got just about as close as we can, but unfortunately, Montana right now, is on complete lock down. The object apparently touched down 40 minutes ago, just north of I-94. We're waiting to hear if this is perhaps an experimental vessel or. . . Hold on. I'm learning that more objects like this have landed in as many as eight other locations around the world. Yes? Can we? This is from a site in Hokkaido. This is worldwide. It is happening right now.

A school alarm sounds off.

Louise: Okay, I'm sorry, class is dismissed.

Walking to her car, Louise sees fighter jets fly by. Early signs of mass panic begin such as school traffic jamming up as hundreds of students try to leave and parking lot fender benders. In her car, she listens to a radio report.

Radio Anchors: . . . . . is simply asking for cooperation while authorities assess the object. You're saying it's not ours? Do you even know if it's from Earth? We are still collecting information. We're coordinating with other countries. We are not the only ones to have one of these in our backyard. If this is some sort of peaceful first contact, why send twelve? Why not just one?

At her home, she talks on the phone with her mother and later continues watching the news.

Louise: Yeah, I know, I saw that too. I don't know, Mom. I'm watching the same news coverage you are. Mom, please don't bother with that channel. How many times do I have to tell you? Those people are idiots. Yeah, well do I sound nervous? Ok. Exactly. So . . . Me? Yeah, you know me. I'm about the same. Mom, I'm fine. Ok, I'll call you later. Bye.

TV Anchors: And around eight hours after landing, there's still no signs of what might be called "first contact." Now, the objects measuring at least 1500 feet tall. Two more have reported to have penetrated Russian airspace. One in Siberia and the other off the coast of the Black Sea, above the ocean. So far there are twelve unidentified objects spread across the globe. There is no obvious logic to their locations and no evidence that the ships are even occ . . . . . . entertain the idea that if it is a kind of vessel, it may be unmanned. Regardless, we have a protocol for scenarios like this.

Further TV news coverage shows mass panic is beginning to escalate. Large crowds gathering, shouting, chanting. Security forces are called in.

The next day, she returns to the school to give her next lecture session, but this time there are zero students in the class room. She goes to her school office and watches the news on her laptop.

TV Anchor: After Tuesday's extraordinary events, the President this morning, has declared a state of emergency with as many as 5,000 National Guard being deployed to the state of Montana alone. Borders are closed and flights have been grounded, stranding millions of travelers.

TV Anchor: Panic buying of gas, water and food continues to escalate and federal authorities have temporarily lifted all caps on overtime for law enforcement. The ATF has put a temporary ban on new gun licenses, forcing many independent suppliers of hunting equipment and firearms to close their doors to the public. Forty-eight hours later and no further development from sites of the UFOs.

Colonel Weber (Forest Whitaker) enters her office.

Weber: Two days. And already, the public expects us to know all the answers. I'm Colonel G.T. Weber. We have never formally met, but two years ago, you did some Farsi translations for Army Intelligence. You made quick work of those insurgent videos.

Louise: And you made quick work of those insurgents.

Weber: You are on the top of everyone's list when it comes to translations. And you have another two years in the SSBI, so you still have top secret clearance. That's why I'm in your office and not in Berkeley.

Louise: Okay.

Weber: I have something I need you to translate for me.

Voice recording: Why are you here? Do you understand us? Where did you come from?

She then hears strange voices, not human. Low pitch growls.

Weber: Now you heard it. What do you make of it?

Louise: Is that . . . ?

Weber: Yes.

Louise: How many?

Weber: How many what?

Louise: How many speaking?

Weber: Two. Assume they were not speaking at the same time.

Louise: Are you sure they had mouths?

Weber: How would you approach translating this? Do you hear any words? Phrases?

Louise: I don't know.

Weber: So what can you tell?

Louise: I can tell you that it's impossible to translate from an audio file. I would need to be there to interact with them.

Weber: You didn't need that with the Farsi translation.

Louise: I didn't need because I already knew the language, but this is. . .

Weber: I know what you're doing.

Louise: Tell me what I'm doing.

Weber: I'm not take you to Montana. It's all I can do to keep it from turning into a tourist site for everybody who has a TS clearance.

Louise: I'm just telling you what it would take to do this job.

Weber: This is not a negotiation. If I leave here, your chance is gone. . . . . Good day.

Louise: Colonel? You mentioned Berkeley. Are you going to ask Danvers next?

Weber: Maybe.

Louise: Before you commit to him, ask him the Sanskrit word for "war" and its translation.

At night, Louise is lying in her bed with the TV news on.

TV Anchor: An agreement on sharing scientific discoveries was closer tonight as Russia and China join talks at the United Nations. Meanwhile, financial markets across the world are in crisis as the Dow Jones Industrial Average fell 2,000 points.

Aircraft roaring. Weber shows up in a helicopter to escort Louise to the base.

Weber: Morning.

Louise: Colonel?

Gavisti. He says it means "an argument." What do you say it means?

Louise: A desire for more cows.

Weber: Pack your bags.

Louise: All right, give me 20 minutes.

Weber: We take off in ten.

There are number of men on board, including Ian Donnelly (Jeremy Renner).

Soldier: Doctor Banks. Right this way, please.

Pilot on radio: . . . ready to approach.

Soldier: Excuse me, Doctor Banks, let me make sure you're properly secured.

Weber: You okay?

Louise: Yes.

Ian begins talking to her, but his words are inaudible due to the engine noise. Weber points to the headphones near her, she puts them on.

Louise: Sorry, I couldn't hear what you were saying.

Ian: "Language is the foundation of civilization. It's the glue that holds the people together. It's the first weapon drawn in a conflict."

Weber: Louise, this is Ian Donnelly. Louise Banks, Ian Donnelly.

Louise: That's quite a reading.

Ian: Yeah . . . you wrote it.

Louise: Yeah. It's the kind of thing you write as a preface. Dazzle them with the basics.

Ian: Yeah, it's great. Even if it's wrong.

Louise: It's wrong?

Ian: The cornerstone of civilization isn't language, it's science.

Weber: Ian is a theoretical physicist from Los Alamos. You'll be reporting to me, but you will be working with him when you are in the shell.

Ian: That's what they're calling the UFO.

Weber: Priority One: what do they want and where are they from?

Ian: And beyond that, how did they get here? Are they capable of faster than light travel? I've prepared a list of questions to go over, starting with a series of "handshake" binary sequences.

Louise: How about we just talk to them before we start throwing math problems at them?

Weber: This is why you're both here.

Ian: I'll bring the coffee. Coffee with some aliens.

The team arrives at the Montana landing site, while the other 11 sites around the world have bases set up as well and are continuously updating each other on any progress.

Louise sees the alien ship for the first time, other than TV.

Weber: I want you to take these two to Doctor Kettler.

Captain Marks: Yes, sir.

They notice someone being carried away in a medevac.

Weber: Follow the Captain to medical. It should take just a few minutes, and then we'll get started.

Alright.

We'll take care of your bags. I'll take your cell phones. Follow me. Put these on. You're gonna wear them at all times [security badges]. Sir, they're here.

Dr. Kettler: Louise Banks? Ian Donnelly? When was the last time either of you have eaten?

Louise: Last night.

Ian: Same.

Dr. Kettler: Last time you did something stressful?

Ian: Does now count? Just saying.

Louise: Who was being carted off in a medevac?

Dr. Kettler: Not everyone is able to process experiences like this. I'm gonna get some blood from you and give you an immunization dose that covers against a battery of bacterial threats. Can you sign these, please? And roll up your sleeves. Before we can start. Either of you claustrophobic?

Both: No.

Dr. Kettler: Currently taking any medications? Allergies? Pregnant? The booster is a kick to your system, so you may experience some side effects, nausea, dizziness, headaches, or a ringing in your ears, like you have tinnitus.

Louise and Ian are escorted to a communications tent.

Man: They wouldn't go, either way.

Soldier 1: You see what's happening to him?

Soldier 2: How does this even work?

Australian Scientist: The readings do not change, it's like we're insects on a piece of paper, and they're easing us out of the house. At exactly 112 minutes and 19 seconds, gravity starts to shift and slides us out of the room.

A man known as Halpern (Michael Stuhlbarg) responds to the scientist on the monitor, Ian and Louise join him.

Halpern: Have you found a scientific explanation for it? Like is it for them?

Australian Scientist: No, I think it's for us. Air doesn't seem to circulate inside the chamber, so after about two hours, we run out of oxygen.

Halpern: It doesn't take 18 hours to pump fresh air into a room.

Ian: Atmosphere.

Halpern: Excuse me?

Ian: If their atmosphere is different from Earth, it would certainly take hours to rebalance their O2 content and pressure for us every time they open their door.

Halpern: So, you're saying they could suffocate us if they wanted.

Weber: This is Agent David Halpern with the CIA. Let me get you two to your stations. Remember, we need answers as soon as possible. What do they want? Where are they from? Why they are here? This is the priority.