It's important when engaging with many forms of media to avoid spoilers, because knowing what's going to happen next makes everything bad. This is why no one has ever watched a movie they enjoyed twice. So now I present my new feature, a spoiler-free review!
To ensure it is completely free of spoilers, I have not yet watched the movie myself.
I believe it stars Captain America (Captain America's name is Steve. That's not a spoiler unless you haven't seen the first two Captain America movies or the Avengers movies or Agent Carter or probably it's mentioned in some of the other movies. So I guess it's a spoiler for those movies, but I'm not reviewing those movies so technically this review is still spoiler-free) and Iron Man (Tony Stark, and pretty much everyone knows that, both in universe and out), and they are somehow propelled back in time to the american civil war. They team up with Bucky, Underoos, and several other people based on the trailer, and they mostly fight each other, probably as a warm up drill. The story comes to a dramatic finish when Tony and Steve discover that both of their mothers were named Martha, and the resulting paradox enables them to travel back to the present just in time to stop Loki from stealing the infinity gauntlet.
Or something like that.
Still, there's fighting, probably. Everyone loves watching fighting. 10/10