This movie has both the intense comic-book action expected of a Marvel movie and complex character conflict. (MILD SPOILERS) It is centered around the Sokovia Accords, which gives complete control over the Avengers to the UN, and how it splits them into two teams, Team Cap and Team Iron Man. Iron Man, who helped create the Accords, believes that, as he puts it, they "need to be put in check," while Captain America believes that a) the UN, and the government, are "run by people with agendas," and that b) - when it comes to safety, "the safest hands are still their own." Basically that the UN might use the Avengers for their own doing, and that the UN isn't going to know about every threat. I can see both sides to this argument, and don't 100% agree with either, although I'd probably say I lean towards Iron Man. The film also acts like your traditional sequel, as it continues the Winter Soldier's and Captain America's character arcs from Winter Soldier (which is also excellent) by having Cap go after him and try to help him be Bucky again. Overall, great action, great plot, great characters, great film.