Following the Battle of Sokovia, the latest in a series of high-profile incidents involving the Avengers, public opinion worsened as the nations of the world began demanding government oversight. The following year, the Avengers were once again thrust into the spotlight after a disastrous operation in Lagos killed twenty-six people, eleven of them being relief workers from Wakanda, and caused $14 million in property damage.
In response, the United Nations passed the Sokovia Accords and established a panel that would control the Avengers' movements. While the team became divided over the impact that the accords would have, with Steve Rogers opposing the idea of international oversight and Tony Stark supporting the idea, the accords were ratified.
Three days later, the United Nations hosted a formal ceremony at the Vienna International Centre in Vienna, Austria. As Wakanda's reigning monarch T'Chaka gave the keynote address, a bombing attack decimated the Centre, killing T'Chaka and twelve others. When security footage revealed Bucky Barnes had orchestrated the attack, Prince T'Challa set out to avenge his father's death.
Rogers, who was attending the funeral of Peggy Carter in London, learned about the bombing and traveled with Sam Wilson to Romania, where Barnes had been living since the Battle at the Triskelion. The two rogue Avengers tracked Barnes to a defunct safe-house in Bucharest only to discover they had been followed by T'Challa. This resulted in a chase that ended with all four being apprehended by the Joint Counter Terrorist Centre and taken to the organization's headquarters in Berlin, Germany.
Upon arriving in Berlin, Barnes was placed in a contained cell while Deputy Task Force Commander Everett Ross arranged for psychiatrist Theo Broussard to perform an evaluation. Before the evaluation could begin, however, a power outage cut the security cameras. Broussard proceeded to recite a set of words that reactivated Barnes' Winter Soldier training, sending the enhanced assassin on a deadly rampage.
Barnes proceeded to make his way to the roof, where he prepared to escape via helicopter only to be stopped by Rogers, who grabbed the landing gear in an attempt to stop the copter from taking off. When the copter fell off the helipad and into the ocean below, Rogers saved Barnes from drowning and pulled him to shore while Wilson escaped with the help of Sharon Carter, who returned their confiscated equipment.
After speaking with newly-appointed Secretary of State Thaddeus Ross, Stark was granted thirty-six hours to bring in his renegade comrades and assembled a small team composed of T'Challa, James Rhodes, Natasha Romanoff, and Vision. Stark then traveled to New York City, where he recruited Peter Parker, an ordinary high school student with spider-like abilities, under the pretense of giving him a scholarship.
Meanwhile, Barnes told Rogers and Wilson that the man claiming to be Broussard wanted information about a HYDRA facility where five other Winter Soldiers were being kept in suspended animation. After enlisting Clint Barton to rescue Wanda Maximoff and recruit Scott Lang, who had been recommended by Wilson, Rogers and his team made their way to Leipzig-Halle Airport, where a Quinjet was waiting to take them to Siberia.
Iron Man evacuated the airport, alerting Captain America and his team to the heroes' presence. Captain America jogged out onto the runway towards a helicopter, which was then quickly disabled by Iron Man as he, War Machine, Black Panther and Black Widow approached Captain America. Captain America attempted to convince them that Barnes was innocent, however, Iron Man grew impatient and ordered Spider-Man to web Captain America's hands and steal his shield.
Falcon soon located the Quinjet and notified Captain America, who then gave the signal to Hawkeye. Hawkeye fired an arrow at the webbing, freeing Captain America as Ant-Man revealed himself to be hiding on Captain America's shield and managed to take Spider-Man by surprise, hitting him and retaking the shield. Stark turned around to the source of the arrow, locating Hawkeye and Scarlet Witch via scan as War Machine announced Falcon and Barnes' position and the battle began.
Spider-Man, still inexperienced, asked Iron Man what he should do, who repeated that he should keep his distance and shoot webs to harmlessly subdue them. Black Panther immediately headed for Barnes' location, but was quickly stopped by Captain America, refusing to let him kill his friend. Ant-Man casually and naively told Black Widow he'd rather not hurt her, Romanoff responded by kicking him and spinning him around. Ant-Man quickly reacted by shrinking and flipping her over, however Black Widow zapped and launched him away with her bite.
Spider-Man smashed through the airport's terminal window, kicked Falcon down and effortlessly intercepted a punch from the Winter Soldier's Prosthetic Arm, revealing his superhuman strength. Spider-Man became distracted at the arm until he was tackled by an airborne Falcon, who carried him up into the air. Meanwhile, the fight between Captain America and Black Panther continued, Rogers struggling to hold back both
Black Panther as well as War Machine, who took hold of his War Hammer to join in on the fight. Black Panther caused a notable claw mark on Captain America's shield using his vibranium claws. As this occurred, Iron Man caught up to Hawkeye and Scarlet Witch, firing missiles around them to force them to stop running. After a brief conversation, Hawkeye distracted Iron Man by purposefully missing arrow shots which allowed Scarlet Witch to drop cars from above on top of Iron Man, temporarily immobilizing him.
Back in the terminal, Spider-Man chased Falcon through the room before using his spider-sense to quickly dodge a heavy object thrown from behind him by the Winter Soldier, throwing it back in his direction. Falcon tackled Spider-Man a second time, but Spider-Man maneuvered above him and disabled his thrusters with web, causing him to fall to the ground and smash through a stand. Spider-Man quickly webbed Falcon's arms to a glass barrier before he could escape and went on to ask if Falcon's wings are made of carbon fiber.
Falcon reminded him that you usually don't have conversations while fighting and Spider-Man responded by swinging towards him in an attempt to kick him in the chest. Barnes quickly ran in front of Falcon to absorb the hit, but both still fell through the glass barrier and onto the floor below before being webbed again by Spider-Man. Before Spider-Man can fully immobilize the two of them with more web, Falcon quietly ordered Redwing to grab his arm and throw him out of the window. Barnes murmured that he should have done that sooner, to which Falcon replied that he hates him.
Outside the terminal, Captain America kicked War Machine, destroying his War Hammer. Then, he kicked Black Panther away, besting both opponents. Ant-Man joined Captain America and gave him a shrunken down truck filled with fuel, telling him to throw it at one of his blue Pym Particles Disks. Ant-Man threw the disk in the air and Captain America did as he was instructed, the truck returned to its regular size, blowing up and slamming into War Machine shortly afterwards. The two ran off and regrouped with Hawkeye, Scarlet Witch, Falcon and Barnes as they sprinted to the Quinjet.
Before they could reach it, Vision arrived at the airport and stopped them by firing a warning beam across the floor. Vision used this time to give Captain America one last chance to surrender, while also giving Iron Man's faction enough time to regroup as well. Captain America refused to surrender, and began to charge alongside his faction. Iron Man, also refusing to back down, did the same. The two sides slowly built up speed before they all clashed together in combat, eventually splintering off into individual fights.
Among all the other chaos, Black Widow and Hawkeye exchanged hits as Black Widow jokingly asked if they were still friends to which Hawkeye responded that it depended on how hard she hit him. Black Widow flipped the distracted archer and almost dealt a finishing blow to the head before Scarlet Witch intercepted it and knocked Romanoff out. Scarlet Witch scolded Hawkeye for pulling his punches before leaving to help the Winter Soldier. Black Panther had immediately begun fighting Barnes and refused to listen to anything he said in his own defense. Before Black Panther got the chance to claw Barnes' neck, Scarlet Witch stopped him and threw him away.
Captain America threw his shield and cut through Spider-Man's webbing as he was swinging around, dropping him to the floor. Spider-Man was once again interested by Captain America's faction's equipment and complained that his shield doesn't obey the laws of physics. Captain America told Spider-Man that he doesn't understand what's going on, Spider-Man remarked that Stark said he would say that and began to follow the advice given by Stark on how to beat Captain America. However, despite the advice from Iron Man and Spider-Man's superior abilities, Captain America still came out on top due to his experience, dropping a plane bridge on top of Spider-Man to temporarily immobilize him.
Meanwhile, Falcon requested help from Hawkeye to get Iron Man off his back. Ant-Man climbed onto Hawkeye's arrow and was launched alongside it, the arrow splintered into several pieces to distract Iron Man as Ant-Man leapt from the arrow, ran up an unsuspecting Iron Man's arm and slid into a crack in his armor. Iron Man, now fighting Hawkeye, began to have several of his suit's weapons systems go offline. Ant-Man made his presence inside the suit known as he joked that Stark would need to bring his suit into the shop, which backfired as F.R.I.D.A.Y. deployed the suit's fire suppression system, launching him out of the suit before he could cause further damage.
Captain America and Barnes regrouped, Barnes reminding Rogers that Zemo had likely entered Siberia at that point and that they needed to move quickly. Captain America offered to distract Vision as the Winter Soldier took the Quinjet and went alone, however, Falcon, currently being chased by War Machine, told Captain America that this wasn't the real fight and that he needed to be there for the real one. Hawkeye chimed in, telling Rogers that if they want to win, some of them would have to lose. Falcon explained that they'll need a big diversion if they want to be able to let both Captain America and Barnes escape in the Quinjet, to which Ant-Man responded that he has something 'big.'
He told Captain America to run at his signal, as he jumped onto War Machine's leg and became Giant-Man, increasing his size to several stories high and capturing the attention of everyone. He grabbed War Machine and threw him across the airport, Spider-Man barely catching him with a string of web before he crashed into a plane.
As Giant-Man, Lang began to kick and throw large objects towards Iron Man's faction, not limited to a plane wing thrown at Iron Man during his fight with Falcon and a bus kicked towards Black Panther, but was narrowly protected by Vision, who blocked the bus just in time, as he attempted to chase the Winter Soldier. Iron Man asked if anyone on his team had any abilities they wanted to disclose before Falcon temporarily closed his wings midflight and launches Redwing into Iron Man's helmet, destroying it in the process.
Black Panther was blocked by Giant-Man once again in his attempt to reach Barnes, who kicked him over and was in the process of kneeling down to grab him as he was peppered with non-lethal rounds from War Machine, who was carrying Spider-Man. Spider-Man leaped from War Machine onto Giant-Man, swinging around his arm before kicking him in the face. Below, Hawkeye introduced himself to Black Panther after firing multiple arrows at him, to which Black Panther responded that he doesn't care. The two engaged in hand to hand combat as War Machine continued to attack Giant-Man, eventually firing his full arsenal at him as he attempted to crush War Machine with a bus.
Vision, after attacking Lang, became aware of Captain America and Barnes' escape, and decided to destroy the tower next to the Quinjet's hanger to block the entrance. Scarlet Witch quickly used her powers to slow down the fall of the debris, until War Machine used his Stark Sonic Cannon to knock her unconscious. Rogers and Barnes were forced to slide under the debris as it fell before being greeted by Black Widow as they finally reached the Quinjet. Black Widow came to terms with the fact that Rogers wasn't going to change his mind, and decided to help him by betraying her side by once again using her bite, this time on Black Panther, who had since ended his fight with Hawkeye and given chase, holding him back by firing Taser Disks.
As the rest of Iron Man's faction were still in the process of fighting Giant-Man, Spider-Man came up with the idea to lock his legs together which he remembered from a "really old movie" called The Empire Strikes Back. Lang, slowed down in Giant-Man form, was unable to respond to Spider-Man spinning around his legs tying him up with web as Iron Man and War Machine teamed up and punched Giant-Man in the head, knocking him down and taking him out of the fight for good (not without accidentally knocking Parker as he fell, however). Stark landed to see if Spider-Man was okay before ordering him to go home, lest the sustain further injuries, thanking him for the job he did and threatened to call Aunt May if he didn't. Parker, feeling that he disappointed Stark, tried to convince him that he was okay, but soon admitted that he was done.
Piloting the Quinjet, Captain America finished shooting down the debris in the way of the hanger entrance before leaving, despite Black Panther's best efforts to stop him. Vision flew over to a recovering Scarlet Witch and they apologized to each other for fighting. War Machine and Iron Man began following the Quinjet, with Falcon not far behind. Falcon began peppering Rhodes with missiles and Rhodes responded by requesting Vision to disable Falcon's thrusters so he would be forced to safely glide down to the ground.
Vision, distracted, fired an abnormally powerful beam at Falcon who quickly dodged it. The beam continued through the air and cut through War Machine's suit, destroying its Arc Reactor and completely disabling the suit. Rhodes, trapped inside the suit and unable to control it, began to plummet to the earth. Both Falcon and Iron Man stopped chasing the Quinjet and flew down in an effort to save Rhodes, but neither were fast enough and he slammed into the ground. Stark landed and tore off the helmet's mask, revealing Rhodes to be unconscious. F.R.I.D.A.Y. read his vitals and informed Stark that he was still alive and a medical team was on way. Wilson landed and told Stark that he was sorry. Stark, distraught, blasted Falcon in the chest, signalling the end of the conflict.
Following the Clash, Clint Barton, Scott Lang, Wanda Maximoff, and Sam Wilson were captured and imprisoned in the Raft while Peter Parker was sent back to New York City by Tony Stark's request. James Rhodes, meanwhile, survived his fall but suffered severe spinal injuries that temporarily ended his career as a soldier and Avenger. Natasha Romanoff, knowing full well she too would be arrested for her actions, went into hiding.
While en route to meet Secretary Thaddeus Ross at the Raft, Stark learned from F.R.I.D.A.Y. that Theo Broussard had been found dead at a Berlin hotel and that the man who interrogated Bucky Barnes was former Sokovian intelligence officer Helmut Zemo. When F.R.I.D.A.Y. noted that a wig and facial prosthesis approximating Barnes' appearance were also found, Stark realized Rogers had been telling the truth.
Stark tried to tell Ross about what he had learned only to be turned away. Taking matters into his own hands, he caused a temporary audio failure and interrogated Wilson, who reluctantly revealed where Rogers and Barnes were headed. After lying to Ross about what he had learned from Wilson, Stark left the Raft and donned the Mark XLVI armor once out of visual range, unaware that T'Challa was following him.
- Captain America: Civil War
- Agents of S.H.I.E.L.D.
- Spider-Man: Homecoming (mentioned)
- Captain Marvel Prelude (footage)
- Ant-Man and the Wasp (mentioned)
- Avengers: Endgame (mentioned)