Millions of years ago, a meteorite composed of vibranium hit the continent of Africa, causing vibranium to spread throughout the surrounding land. Five African tribes would later settle upon the vibranium-rich land, naming it "Wakanda", and become engaged in constant war with one another until one tribesman obtained a heart-shaped herb with the help of the goddess Bast. The herb gave him superhuman strength, speed and senses, enabling him to become the first Black Panther and unify four of the tribes - The Merchant Tribe, the Border Tribe, the River Tribe and the Mining Tribe - under his rule. The fifth tribe, the Jabari, chose to isolate themselves in the mountains rather than live under the Black Panther's rule, while the other four tribes formed Wakanda proper and used vibranium to develop highly advanced technology. To avoid being threatened by other nations, Wakanda posed as a poor third-world country to the outside world.
In 1992, Prince N'Jobu, who has been stationed in Oakland, California as a wardog - a Wakandan spy - plots to break his wife out of prison when he is confronted by his brother T'Chaka, the current Wakandan King and Black Panther. T'Chaka accuses N'Jobu of helping arms dealer Ulysses Klaue steal some vibranium from Wakanda, with N'Jobu's friend revealing himself to be Zuri, another wardog, and confirming the king's accusations. T'Chaka orders N'Jobu to return to Wakanda and explain himself.
24 years later, the new Black Panther, Prince T'Challa, returns home to be crowned King of Wakanda, following the Sokovian Accords attack that killed his father and led to the dissolution of the Avengers. He is reunited with his mother Queen Ramonda and his sister Princess Shuri, the head of Wakanda's science research division. As part of the coronation ceremony, T'Challa is stripped of the herb's powers, and members of the royal family and other tribes are allowed to challenge him for the throne. None of them do until the Jabari Tribe unexpectedly crash the ceremony, with their leader M'Baku challenging T'Challa in response to both Shuri's lack of respect towards Wakandan traditions and T'Challa's failure to prevent T'Chaka's death. After a tough fight, T'Challa overpowers M'Baku and convinces him to surrender rather than fight to the death for the sake of his people.
His right to rule proven, T'Challa retakes the herb's powers and converses with the spirit of T'Chaka in a spiritual plane of existence known as the Ancestral Glade. The deceased king expresses pride in his son, calling him, "a good man, with a good heart", but cryptically warns him that, "it's hard for a good man to be a king."
Meanwhile, Klaue and a young African-American man named Erik Stevens steal a disguised vibranium artifact from a museum in London, killing several guards in the process, and make plans to sell it at an underground casino in Busan, South Korea. T'Challa learns of Klaue's plans, and travels to Korea with Okoye - the leader of the Dora Milaje, Wakanda's elite all-female royal bodyguards - and Nakia, his ex-girlfriend and another Wakandan spy, in order to apprehend him, while Shuri provides tech support from Wakanda. Before leaving, T'Challa makes a promise to W'Kabi, Okoye's husband and leader of the Border Tribe - who lost many of their people to Klaue during his 1992 raid, including W'Kabi's parents - to bring the arms dealer back to Wakanda dead or alive.
In Busan, the Wakandans run into Everett Ross, Klaue's buyer, who hopes to bring him in for the CIA. Okoye is compromised during the operation, leading to a massive gunfight in the casino and then a car chase through the streets, after which Klaue is captured and taken to a CIA hideout. Klaue gives hints of Wakanda's true nature to Everett during his interrogation, and is later broken out when Erik attacks the hideout. T'Challa notices that Erik has a ring bearing the Wakandan royal seal, and Everett is shot in the spine while protecting Nakia. Despite Okoye's reservations about aiding a foreign intelligence agent, T'Challa has Everett taken back to Wakanda to be treated. W'Kabi expresses disappointment at the failure to capture or kill Klaue, claiming that T'Challa is no different than his father.
Meanwhile, Erik kills his mistress, turns on Klaue and fatally wounds him, after revealing his intentions of traveling to Wakanda. Klaue warns him that the Wakandans will see him as an outsider and treat him accordingly... to which Erik reveals a wardog tattoo on his lower lip. Klaue laughs in his dying moments when he sees that his partner isn't just some American kid, before Erik puts him down for good.
Thanks to Wakanda's advanced technology, Everett is completely healed in less than a day, and he becomes the first white man besides Captain America, Bucky Barnes, and Klaue to learn of Wakanda's true nature. Meanwhile, T'Challa questions Zuri about Erik. Zuri reluctantly reveals the truth: Erik is actually N'Jadaka, the son of N'Jobu and T'Challa's long lost cousin. He further explains that in 1992, N'Jobu had wanted to supply people of African descent with vibranium weapons in order to allow them to fight against their racist oppressors. When T'Chaka confronted him and demanded he come back to Wakanda to stand trial, he tried to pull a gun on Zuri, prompting T'Chaka to kill him in self-defense. To maintain Wakanda's cover, T'Chaka swore Zuri to silence over what happened, and the two of them abandoned N'Jadaka.
N'Jadaka hands Klaue's body over to W'Kabi, in exchange for a meeting with T'Challa and the tribal elders. Everett then reveals to the Wakandans that N'Jadaka is in fact a U.S. Black Ops soldier known as "Killmonger", owing to his impressive kill count, who specialized in dismantling governments that posed a threat to American interests.
Killmonger enters the Wakandan throne room and tries to convince T'Challa to provide vibranium weapons for oppressed blacks across the world. When this fails, he reveals his true identity and challenges T'Challa for the throne, wanting to kill the king in revenge for his father's death at T'Chaka's hands. T'Challa accepts the challenge, but tries to avoid killing Killmonger, allowing Killmonger to gain the upper hand in the battle. Before he can land the killing blow, Zuri intervenes, claiming that he is the one who caused N'Jobu's death. Killmonger murders him, and throws T'Challa over a waterfall, seemingly killing him.
Killmonger is acknowledged as king, obtains a Black Panther suit of his own and takes the heart-shaped herb for himself, after which he orders all samples of it destroyed. Nakia manages to sneak away an herb for herself, before she, Shuri, Ramonda and Everett flee, while Okoye and the Dora Milaje - whose loyalty is to the Wakandan throne rather than T'Challa personally - reluctantly remain to serve Killmonger. Assuming the throne, Killmonger reveals his intention of establishing a Wakandan empire that spans the globe, an idea that is opposed by Okoye, who believes that Wakanda should only ever fight to protect itself, but supported by W'Kabi, who fears that the rest of the world is catching up to Wakanda's technology in the arms race, and will soon be in a position to threaten them.
Nakia, Shuri, Ramonda and Everett travel to the Jabari lands and offer the herb to M'Baku, seeing him as a lesser evil than Killmonger. M'Baku instead reveals that the Jabari have been taking care of T'Challa, who survived his fall and is currently in a coma, and allows them to give him the herb as thanks for sparing M'Baku's life. Returning to the Ancestral Glade, T'Challa meets the spirits of his father and the previous Black Panthers, who try to convince him to join them in the afterlife. Instead, T'Challa furiously denounces his father's abandonment of Erik and the other isolationist actions of the past kings, claiming that it's that attitude that led to Killmonger becoming the menace he is today. He resolves to return and depose Killmonger, with Nakia, Shuri and Everett all agreeing to help. M'Baku is also asked to lend aid, but he refuses to commit Jabari lives to T'Challa's struggle after so much time separated from the rest of Wakanda. T'Challa warns that Killmonger will soon come for M'Baku and the Jabari, but M'Baku is still not convinced, so T'Challa and the others leave.
Back at Wakanda's capital, Killmonger and W'Kabi prepare to ship vibranium weapons to Wakandan spies in London, New York and Hong Kong, where they will be distributed among black communities and used to incite violent revolutions there, and then across the globe... but then the first of the weapons transports is suddenly shot down by an unseen attacker. It crashes, and T'Challa emerges from the wreckage in his Black Panther Suit.
W'Kabi and the Border tribe attack T'Challa, while Okoye and the Dora Milaje turn on them and Killmonger, for as T'Challa points out, the question of who is the rightful king of Wakanda is still up for debate. As the battle takes place, Shuri and Nakia sneak Everett into Shuri's lab, where he uses Shuri's technology and his own piloting skills to remotely control a Wakandan aircraft and destroy the transports carrying the weapons. Nakia and Shuri then take part in the battle, and Killmonger nearly kills the latter, but he is tackled into the underground vibranium mines by T'Challa, where the two princes battle to the death. W'Kabi, the Border tribe and their war rhinos overwhelm Nakia, Shuri, Okoye and the Dora Milaje, but the tide of battle is unexpectedly turned when M'Baku and the Jabari show up, and W'Kabi and the Border tribe surrender after Okoye warns W'Kabi that as much as she loves him, she will not hesitate to kill him for the sake of Wakanda.
Down in the mines, T'Challa takes advantage of the vibranium dampeners - devices used to nullify vibranium's properties and make it safe for transport - to disable Killmonger's suit and fatally stab him with a broken-off spear head. Feeling sorry for him, T'Challa assists Killmonger in returning to the surface, allowing the abandoned prince to see a Wakandan sunset for the first time in his life, learning that N'Jobu had described them to his son as the most beautiful in the world. T'Challa then offers to try and have Killmonger's wound healed, but Killmonger chooses to die rather than be incarcerated, and asks that he be buried at sea, with the Africans who chose to jump from slave ships. With the conflict over, T'Challa returns to the throne, replaces W'Kabi with M'Baku on his ruling council, gets back together with Nakia, and decides to end Wakanda's isolationist policy and share his country's resources and technology with the rest of the world, to prevent other black people from having to go through what Killmonger did.
T'Challa appears at the United Nations and announces his intentions of having Wakanda foster better relations between the people of the world. One of the delegates patronizingly asks what "a nation of farmers" can do, to which T'Challa and Everett - who is attending the speech - both give knowing smiles. T'Challa buys out the property where N'Jobu had been killed in order to build an educational center for impoverished black American children.
Later, Shuri visits a small Wakandan village where she notices a trio of children running from a hut after staring at the man inside it. The occupant of the hut then exits it, revealing himself to be a recovered Bucky Barnes. He assures Shuri that he's fine, and the two of them walk off, Shuri stating that Bucky still has much to learn.
