Busan, formerly known as Pusan, is the second largest city in South Korea.
Black Panther learned that weapons dealer Ulysses Klaue planned to sell a stolen Vibranium artifact in Busan. Therefore, Black Panther took Okoye and Nakia with him to Busan in order to arrest Klaue. They entered Jagalchi Market Casino and waited for Klaue to come. However, Black Panther recognized Everett Ross among the customers and identified him as Klaue's buyer.
Klaue eventually arrived in the casino and met with Ross. As the transaction was being made, Okoye was recognized as a hostile by Klaue's bodyguards. A shootout erupted in the casino and although Black Panther, Nakia and Okoye defeated several bodyguards, Klaue managed to escape in a column of SUVs. Nakia and Okoye took their car to chase him, leaving Black Panther behind to catch up with them thanks to Shuri.
A hot pursuit engaged in the streets of Busan. After they damaged most of Klaue's SUVs, Klaue destroyed Okoye's and Nakia's car, leaving only Black Panther to chase Klaue. Klaue destroyed the car Shuri was remotely controlling, but Black Panther used the kinetic energy absorption of his suit to destroy Klaue's car. Klaue's was then stripped of his prosthetic arm and delivered to the CIA, to be taken to the CIA South Korean Black Site.
In the CIA site, Ross interrogated Klaue, who revealed the true nature of Wakanda, a rich African country heavily relying on Vibranium. However, while Ross confronted Black Panther about the matter, Erik Killmonger blew a hole in the wall to rescue Klaue. Another gunfight erupted, in which Ross was heavily injured while Black Panther failed to stop Killmonger and Klaue. Facing this defeat, Black Panther, Okoye and Nakia left Busan with Ross.