The movie consists of 2 sides one for the heros
one on iron man Tony stark`s side and another on captain`s
Actually because of the whole Avengers team tried to defeat bad guys in different contries many civilians are dead in fight between avengers and villans thus the total union of the whole contries around the globe decided to take control over Avengers but on super heros side they disaggred and the team splits into two.
here the team of iron man side fights with the team of super powered heros against each other.
finally at the end the come together but a civillian who lost his family in yhe fight of avengers and villans has came to avenge their deaths and just make captain to fight against iron man.
thus the story again ends with split of Avenges team.
the film action can be greatly enjoyed in 3D.