Marvel fans have been begging for the release of a trailer for the long-anticipated movie "Captain America 3: Civil War." Comic fans know that this storyline pits Steve Rogers and Tony Stark, aka Captain America and Iron Man, against each other. When we last saw them in "Avengers: Age of Ultron," the two had appeared to put their differences aside for the greater good, which may have many people asking what happened to set them against each other. Well, it’s pretty simple. Steve’s best friend is back from the dead and the government wants to kill him, and they want everyone with superhero abilities to register and work for them. Easy enough, right?

The trailer picks up where the bonus scene from "Ant-Man" left off. Steve Rogers and Sam Wilson have finally found James “Bucky” Barnes. Bucky was Steve’s best friend, and was presumed dead during World War II. However, as we saw in the last "Captain America" movie, Bucky had actually been taken in by Hydra, a group that was originally created by Nazis. Hydra desires control, stability, and order, and is unafraid to do whatever it takes to fulfill their new world order. They brainwashed and tortured Bucky, giving him the codename “Winter Solider” and turning him into an assassin, more machine than man. When they sent the Winter Solider to eliminate Steve, the brainwashing failed when Bucky recognized his friend, however faintly. Since then, he’s been on the run, and Steve and Sam have been trying to bring him home.

Bucky is in what appears to be an abandoned warehouse, his metal arm caught in a vise. Steve asks if he remembers him. Bucky responds, “Your mom’s name was Sarah. You used to wear newspapers in your shoes.” I don't know about you, but I teared up a little.

Steve warns Bucky that he’s a wanted man, to which he replies that he doesn't “do that anymore," and most fans would argue that he never did—he wasn’t aware of his actions during his time with Hydra. Cue the SWAT team running up the stairs to where the heroes are, as Steve says “The people who think you did… they aren't planning on taking you alive.”

Bam! Gunfire! Captain America fighting off government agents! Bucky running and leaping off the building! Then, the red and silver Marvel logo, to remind us the fun is just getting started.

“While a great many people see you as a hero, there are some who prefer the term ‘vigilante,’” says the as-of-yet-unnamed world leader. He goes on to say that Captain America and the rest of the Avengers have operated with unlimited power and no restrictions for too long. The world needs them to have a system of accountability. This is when Iron Man steps on to the scene.

“If we can’t accept limitations, we’re no better than the bad guys,” Tony Stark tells Steve, who disagrees. This is the basis for the disagreement: the government wants all people with abilities to register and be at their disposal; they also intend to capture and execute Bucky, to make an example out of him. Tony wants a system of accountability, something the Marvel Cinematic Universe (MCU) touches upon fairly often. Who pays for the damage done while the Avengers go about saving the day? Tony himself is no stranger to this debate; in the first "Iron Man" movie, he shut down the Stark Industries weapons facility after seeing the weapons in the hands of terrorists. He saw that “[I] had become part of a system that is comfortable with zero accountability,” so it’s understandable that he wants the Avengers, a team he was a part of, to be held responsible for any damage caused. Even heroes need to be held accountable. As we saw in the previous "Captain America" movie, Steve will fight for people’s right to their personal freedom, and forcing people with “abilities” to not only register with, but also work for, the government, is unethical and unconstitutional.

Of course, the trailer is loaded with epic clips of things exploding, people fighting, the Falcon unfurling his wings as he soars off a building, and a brief sighting of the Black Panther, who will be making his first appearance in this movie. There’s also a scene where an entire SWAT team has Bucky cornered, and the only thing standing between them is Steve, putting his shield away. However, it’s the dialogue that hits the hardest (even more than the scene of Bucky and Steve beating up Iron Man, which personally, made me absolutely lose it). Steve tells Tony that he wishes things were different, but Bucky is his friend.

“So was I,” Tony protests. The fact that the two only recently formed a friendship does not, in any way, make that line hurt any less.

How can one two and a half minute trailer cause this much emotional distress? I wish I knew. Though there are many people already taking sides, it’s interesting to explore what each hero stands for, and fans trust that the directors, Anthony and Joe Russo, will do each "team" justice. It’s also important to note that the tagline for this movie doesn't urge viewers to pick a side: in fact, it is the simple reminder that united we stand, divided we fall.