The Army of Scar is a large group of Outlanders led by the spirit of Scar. They wish to take over the Pride Lands. The army is formed when Janja and Ushari revive Scar’s spirit. They are then assigned to get more recruits. After Scar's defeat, the army is disbanded and lives under the rule of Jasiri.
Scar plots with his army in the Outlands to defeat both Simba and the Lion Guard. He explains to his followers that he will be using Sumu the scorpion to take down Simba. He then relishes the irony of taking the day of the Kumbuka celebration and making it into the day that he defeated Simba and the Lion Guard.
Later, Scar gets word of Sumu's success and directs his army to intercept the oncoming Lion Guard. The plan works, with Kiburi, Reirei, Janja, and their respective gangs slowing down the Lion Guard's progress through the Outlands. At last, the Lion Guard reaches the inner volcano, where Makini places a pinch of the cure, volcano ash, in her gourd.
As the team turns to leave, Scar arises from the flames and reveals himself to Kion, admitting his part in the plan to kill Simba. Despite Scar's admission, Kion directs his team to leave, as he is worried about arriving too late to save his father. Scar then calls his army forward, and they corner the Lion Guard at the edge of the lava.
With no option left, Kion steps forward to use the Roar of the Elders. Scar tries to warn Kion that his roar will only cause the volcano to erupt, but Kion informs Scar that he knows more about the roar than Scar ever did. He then uses the roar carefully to blow away Scar's army, and the Lion Guard makes a quick escape.
Scar sends Mzingo and his parliament after the Lion Guard, and the vultures nearly wrestle the gourd from Makini. However, the rest of the team arrives just in time to fend off the vultures, and Kion uses his roar to ensure that they are not delayed again.
At the same moment, Scar overlooks his defeated army and comments that the war has only just begun.
While the Janja, Reirei, and Kiburi speak with Scar, their minions find and gather unhelpful advice from Thurston. Later the Outlanders try to punish Thurston for leading them astray, but the Lion Guard comes to rescue Thurston.
Scar decides to attack Makuu's watering hole since the crocodiles' alliance with Kion is fraying. The Army of Scar, including Janja and his clan, besieges Makuu's float. Ono witnesses the battle and reports his findings to Kion. Together, the Lion Guard and their Pride Lander allies storm the watering hole and fight off the Army of Scar.
Dhahabu, the queen of the Back Lands, arrives in the Pride Lands to discuss a water treaty between the kingdoms ("Prance With Me"). Scar's lackeys, Shupavu and Njano, spy on the proceedings. In the Outlands, Shupavu and Njano inform Scar of Dhahabu's visit to the Pride Lands. Scar schemes to end the treaty between the two kingdoms and sends Reirei and her pack after Dhahabu.
Across the savanna, Ono discovers that Dhahabu is being set upon by the jackals. Together with Raha and Starehe, the Lion Guard rushes to the rescue and fights off the pack.
Not long after, Dhahabu is freshening up in a water hole when the jackals attack again, this time with crocodile allies. Ono informs the Lion Guard of the predicament, and Raha and Starehe race off to defend their queen.
At Mizimu Grove, Rafiki and Simba announce Makini's mpando mpaya, and Timon and Pumbaa perform their song ("Tujiinue"). In the midst of the celebration, the Army of Scar attacks, and the Pride Landers rise up to defend themselves. The battle pauses when Scar appears in the flames and threatens to overtake the entirety of the Pride Lands. Frightened by Scar's unexpected appearance, the remaining Pride Landers flee Mizimu Grove.