The Battle of Mount Bashenga was a confrontation between the combined forces of the Golden Tribe, the Dora Milaje, and the Jabari Tribe and the combined forces of Erik Killmongerand the Border Tribe.
T'Challa and Erik Killmonger arrived at Warrior Falls in accordance with tradition. Due to being stripped of the Heart-Shaped Herb, T'Challa quickly found himself outmatched by Erik Killmonger's military training and experience and although T'Challa managed to cut Killmonger once, but was ultimately beaten and left badly wounded.
Killmonger decided to finish off the king by throwing him over the falls and declared himself the new king, to everyone's displeasure.
The Jabari Tribe had found T'Challa in the freezing rivers where they fish and brought him back to their domain. Nakia, Ramonda, Shuri, and Everett Ross, having escaped while Killmonger consolidated his power.
With T'Challa comatose and stabilised only by the surrounding snow, Ramonda remembered to use the one Heart-Shaped Herb they stole to bring him back.
T'Challa declared his work wasn't done yet and woke to the relief of his loved ones. T'Challa thanked M'Baku for saving his life and requested that he and the rest of the Jabari help overthrow Killmonger.
M'Baku declined, as he had already repaid his debt to T'Challa. The group left the tribe, with Shuri giving T'Challa his Panther Habit for the upcoming battle.
As Erik Killmonger's agents started delivering Vibranium weapons to War Dog operatives around the world, one of the air crafts exploded and crashed, with T'Challa emerging from the wreckage.
T'Challa then challenged Killmonger, stating that the Ritual Combat wasn't over. Killmonger ordered W'Kabi and the Wakandan Army to attack T'Challa. Okoye and the Dora Milaje moved to counter, and the Battle for Wakanda began.