A few of the more recent Marvel Films refer back to Civil War such as Ant Man and the Wasp, Black Panther, Infinity War, and Spider-man Homecoming so I thought give a brief plot summary to catch up.
Bucky Barnes was a fellow Army friend of Steve Rogers in the original Captain America film. He ended up being captured by the Nazi run Hydra.
In 1991 we see Bucky has a metal weapon arm and is being trained to be a winter soldier, brainwashed to react to words read from a red book in German.
Present day in Lagos and some of the Avengers are in place to stop Brock Rumlow aka Crossbones from stealing a dangerous biological weapon. Whilst Crossbones does manage to get hold of the deadly compound, himself and his team are defeated by The Avengers. In a last act of revenge on his nemesis Captain America, he blows himself up hoping to take Steve Rogers with him. Scarlet Witch manages to contain the blast using her powers and attempts to lift the blast in to the air to safety when she loses control of it, and blows up a huge section of a civilian building.
With the aftermath of Avengers Age of Ultron is still being felt due to the substantial loss of civilian life in Sokovia, and now this explosion, along with the damage to New York In the Avengers Assemble film it is decided that The Avengers can no longer act on impulse and must be monitored.
The United Nations decide to create a panel to oversee The Avengers asking them to sign Sokovia Accords. The team is divided as some feel their judgements are to save lives and not for the Government to decide.
The member of Hydra that brainwashed Bucky Barnes is tortured by Helmut Zemo for the red book containing the words to reactivate Bucky’s winter soldier training.
In Viena The Sokovia Accords are being discussed in a conference when a bomb explodes killing King T’Chaka of Wakanda. Security footage showed Bucky Barnes had set off the explosion.
With T’Challa , King T’Chaka’s son vowing to avenge the death of his father and the authorities set to capture Barnes, Steve Rogers decides to get to him first for his safety. He heads to Bucharest with Sam Wilson(Falcon) and find Bucky but so does T’Challa(Black Panther). All four end up being arrested by the authorities.
Helmut Zemo impersonates the psychiatrist that was meant to interview Bucky and set off an electrical impulse taking down the communications in the facility, allowing him to say the trigger words to create the winter soldier undetected. This causes Bucky to show extreme aggression and fight his way out of the facility with the help of Steve Rogers who manages to get Bucky to safety to allow him to rest until the effects of the trigger words had worn off.
Wanda has been struggling emotionally, following the explosion in Lagos and is staying under the care of Vision. She attempts to leave to go to the shops and Vision stops her, claiming it was for the safety of others that her powers were contained there.
Bucky tells Steve Rogers that when the communications were down the fake psychiatrist wanted to know the location of the facility where he was held as a winter soldier, and tells him there are more winter soldiers still there in a frozen sleep.
Tony Stark feeling the divide within the Original Avengers, visits my favourite Avenger, Peter Parker to get him on board, after seeing him in action on a You Tube video as Spider-man in his homemade suit. Peter denies that it is him but Stark pops the attic board on the ceiling open and the suit pops down.
Steve Rogers knowing what Bucky can be capable of when the trigger words are said, fears Helmut Zemo is heading to the facility, holding the other winter soldiers, to reawaken them and trigger them to cause a war. As he hasn’t signed the Sokovian Accords he isn’t legally supported to take this action. Along with Bucky and Falcon, he enlists Hawkeye to fetch Wanda to help them and along with new recruit Ant Man create a team in favour of stopping Helmut regardless of the consequences for breaking the Accord.
They attempt to help Captain America and Bucky, leave to stop Helmut and find the winter soldiers when they are challenged by Iron man, Black Widow, Black Panther, Spider-man, War machine and Vision. Spider-man pulled out some moves as did new recruit Ant Man who manages to go giant size to cause a distraction. Black Widow despite being on Iron Man’s team effectively allows Steve and Bucky escape as she is torn morally by fighting her friends.
As Steve and and Bucky leave on the plane War Machine (Rhodes) is shot down by Vision. Was it aimed at Falcon and he missed or was it because he feared the end of the avengers forever unless Steve and Bucky make their journey. Either way neither Iron man or Falcon get to him in time and he is severely injured and partially paralysed.
Falcon, Ant Man, Hawkeye and Wanda are captured and put in Jail. Tony Stark visits, looking as if he is interrogating them he shows falcon his watch with a photo of real psychiatrist who had been murdered by Zemo who was also behind the Vienna Bomb and tells him he wants to help. Falcon tells Stark where they were heading.
Stark Joins Steve Rogers and Bucky Barnes at the Siberian Hydra facility to find all the winter soldiers have been shot dead in there frozen sleep by Helmut Zemo and releasing them into the world was never his intention. He then shows a video of Bucky Barnes under the brainwashed influence of his hydra handler killing Tony Stark’s parents and it transpires that Steve Rogers was already aware of this.
Helmut Zemo’s intentions become clear as he leaves Captain America and Iron man to battle each other effectively destroying The Avengers from within as he knew he wouldn’t have the power to do this any other way.
A Brutal battle occurs between them, in which all three are badly injured with Bucky losing his metal arm, Stark his arc reactor, and Captain America flinging down his shield after being told by Stark he didn’t deserve it.
On the edge of a mountain in Siberia, Black Panther finds Helmut, who explains in Sokovia he lost his dad, wife and child in the Avengers battle with Ultron who was created by Tony Stark so held The Avengers responsible. Helmut goes to shoot himself but is stopped by Black Panther.
Tony Stark recovers and is seen helping James Rhodes with a version of his war machine suit to help him walk again.
Steve Rogers is seen in Wakanda where they are medically treating Bucky.
Stark receives a letter from Rogers saying he was sorry and would help him in the future.
The Jailed Avengers receive a visit from Rogers to help them get out .