The movie opens up with Captain America and his team of two hot chicks (plus the guy with the bird suit) thwarting some evil doers trying to steal biological weapons in Nairobi. In the process, some bystanders are killed.
Then we see Tony Stark (Iron Man) giving away lots of money to MIT students; with the teleprompter by mistake showing that Pepper Potts, his girlfriend and the operator of his industrial empire, as the administrator of the grants. Well, later we find out that she has flown the coop, as she was tired of him being Iron Man. The Manopshere perspective on this is that she should be turned on by Iron Man, but perhaps became an alpha widow from running his empire. Or perhaps there was not enough in the budget to pay her. Dunno.
After the MIT event, this woman corners Tony Stark in the hallway; she tells her story about her totally awesome son who was killed as a bystander in last year’s Avenger Movie. Tony Stark is really moved by this. So when it is suggested that the Superheroes come under the control of the UN, he jumps at the chance due to his feelings of guilt. Which is really kind of stupid for such a smart man as Tony Stark. First the UN is an awful institution that nobody should take seriously; they are undemocratic like the EU, but far worse. Second, when the Superheroes are fighting the SuperBaddies, there can hardly help but be collateral damage. Hiding under the auspices of the UN is not going to do anything about it.
Captain America rightly opposes him on this point, as he believes that the superheroes should have the freedom to do what is right. The superheroes split pretty much evenly on this point, half for and half against. A treaty is about to be signed putting half of the superheroes under UN control. At the big signing event we meet a young African Price and his enlightened father, the King. I am not sure where in Africa one might find such a thing, but this is fiction I suppose. Anyway, the event is bombed, the King dies, and the world is outraged.
Both sets of superheroes are on the case, however Captain America finds out that there is more going on than there seems to be; and is compelled to try to solve the problem himself because he feels that the UN bunch would never believe him. This sets up an epic superhero group against superhero group fight. It was hand-to-hand combat mostly, as that is what viewers want to see. Even the guys who do not have superpowers (they use suits to gain their powers) were fighting suitless hand to hand with fellas with superpowers. I am not sure how that worked.
I will leave the plot here, but there is of course more fighting and twists at the end. However the aspect that pisses me off is that the super smart alpha Tony Stark would submit the horrendous UN. I can’t believe anybody with his level of intelligence would do that. Some writer who probably actually respects the UN probably wrote that in. For me, the superheroes and their superpowers were more believable than this plot point.