If aliens did arrive, how would we feel about that? Awed? Panicked? Fascinated? Worried someone might say the wrong thing? (Note: This is being written before the US election. "Take me to your leader", might be a whole new punchline today).
And what if every country with WWIII-starting capabilities got a spaceship looking like God's high-end speakers parked in their territory?
That's what Arrival tries to capture, in its own low-key, non-Independence Day kind of way.
Yes, it's not the first alien-landing film to do that (cue those five-notes from Close Encounters of the Third Kind ).
And it's not the first to have a smart woman assigned to powhiri visitors from another galaxy - before Amy Adam's linguist in this, there was Jodie Foster's radio astronomer in 1997's Contact.
While Contact was from astrophysicist Carl Sagan, Arrival is from short story writer Ted Chiang and swings toward the "fi" on the sci-fi meter. Especially in its prologue about Adams' character's life and in its final scenes.
And like Contact did, it feels at once profound in the watching but lacking much to remember it by in the aftermath, except for a vague feeling you been told the answer to a puzzle you didn't know you'd been set.
Director Denis Villeneuve's austere approach is certainly impressive and Kubrick-ian, whether it's spaceships that are giant black monoliths, and an opening image as well as costuming that recalls 2001: A Space Odyssey.
But while it gives great atmosphere, Arrival does have moments of story daftness. And, as it heads into its third act, like it's stopped for a reboot.
However, Adams' performance as Dr Louise Banks is terrific. She's the affecting emotional core of this. Especially once she starts her own close encounters with the inhabitants of the ship hovering above rural Montana.
It's her job to decipher the aliens' language, which arrives on the ship's visitors' window as part smoke signal, part fractal, part Rorschach inkblot.
For company, she's got Jeremy Renner's scientist who thinks the only true universal language is maths. You know, banging out "07734" on his calculator and turning it upside down. But he soon defers to his lateral-minded colleague.
As the team makes slow progress, international tensions escalate meaning a breakthrough is needed before it goes all Mars Attacks! or War of the Worlds out there.
It's let down somewhat by where it all ends up.
But when Adams first looks up in wonder at the shadows on the screen deep within the alien spaceship, it's hard not to see it her way.
Cast: Amy Adams, Jeremy Renner, Forest Whitaker
Director: Denis Villeneuve
Rating: M (offensive language)
Running time: 116 mins
Verdict: A new Close Encounters, almost