In a flashback, a young Simba is in a deep gorge when he hears a loud rumbling. He looks up in curiosity to find a massive herd of wildebeest thundering towards him. Simba flees and climbs up a tree for safety, but the weak tree soon gives way to the herd and sends him flying. Luckily, his father Mufasa, the king of the Pride Lands, arrives and catches him in time. Mufasa puts Simba down on a ledge, but the stampede knocks him back into the herd. Mufasa regains his bearings and begins climbing to safety, but is met with the sight of his younger brother Scar, who sneers down at his imperiled brother. Meanwhile, Simba is climbing to safety when he turns back to see his father flailing helplessly as he falls to his death in the stampede.
In the present, a now adult Simba wakes up in horror, realizing it was a nightmare. After taking a look at his sleeping friends Timon and Pumbaa, Simba despondently wanders to a cliff edge to look at the night sky, before lying down again. From the clouds, his father watches over him.
Far away, in a sinister looking crevasse, Sora, Donald, and Goofy teleport in from the Gummi Ship. They have been transformed by Donald's magic into animals. Though they are impressed by their new forms, they are creeped out by the crevasse, and are quickly surrounded by a large pack of hyenas. Donald insists they're just passing through, but their leaders Shenzi and Banzai insist that they stay for lunch, and Goofy quickly realizes that they're the lunch! The trio tries to run, but as they're not used to their new forms, they don't get far. The hyenas are about to chow down when they hear an angry roar from a distance away. Shenzi insists they just let Scar roar, but Banzai convinces her to go as Scar sounds like he's in a bad mood. The hyenas reluctantly leave, and Sora and company spend some time getting used to their new bodies (and Donald notes that Kairi would probably find Sora cute).
The trio enters the Elephant Graveyard where they save the lioness Nala from a group of local Heartless. Nala explains that the Pride Lands where she hails from are a decimated wasteland with no food and water thanks to the tyrannical rule of King Scar. Sora pulls Donald and Goofy aside to discuss things; while he doesn't want to go around knocking kings off their thrones, they still should try to help Nala out - and even suggests he could become their king. The trio agrees to help Nala out, and Nala takes them to Rafiki, the mandrill shaman of the pride, to examine him. However, Rafiki disagrees, telling Nala that Sora isn't fit to be king, much to Sora's disappointment.
Nala tells Sora that his group should leave before Scar finds out they're there, but it's too late, as the hyenas quickly arrive and surround the group. Scar himself arrives, backed up by Pete, who has also transformed into a lion (albeit a big-bellied lion ill-equipped for agile action like Scar). Scar orders the lionesses to hunt and kill Sora and his friends, but Nala attacks Scar to give Sora's trio the chance to escape. She follows thereafter, and when Sora asks if anybody else could be king, Nala says Simba was the next-in-line after King Mufasa died, but he also died when he was a cub. Sora, remembering when he fought alongside Sora during the Heartless invasion, tells Nala that Simba is alive. The group decides to flee the Pride Lands to escape Scar's wrath.
Meanwhile, Timon and Pumbaa are unable to cheer up Simba, who sadly collapses on a cliff which sends some dandruff floating all the way to the Pride Lands. Rafiki finds the dandruff and after reading the tea leaves, realizes Simba is alive, much to his joy. As this is happening, Nala and Sora's group are crossing the perilous terrain of Wildebeest Valley, and Rafiki meets up with them to point them towards the wastelands outside the Pride Lands. Nala realizes Rafiki is pointing them towards Simba and eagerly races ahead.
Soon, Sora and company arrive in a faraway, lush oasis, where they find Simba fending off some Heartless. Sora happily greets Simba, who takes a moment to recognize his now-quadrupedal or flying friends, but is nonetheless overjoyed to see them again. A scream from the jungle alerts them to trouble, and they race in to find Nala about to kill and eat Timon and Pumbaa. Simba attacks Nala to break up the fight, and Sora implores Simba to recognize his old friend. The pair happily reunite, but soon go off for a romantic solo walk through the jungle. However, it quickly turns dramatic as Nala informs Simba of the bad things going on at home, and how Sora proved unworthy to be king as well. Simba refuses, citing "Hakuna Matata" and that he can't change the past.
That night, Simba mournfully remembers the last conversation he had with his father, who told him that he would one day watch over him from the stars. In the present, Mufasa pays heed to his promise and orders his son to take his place in the circle of life. When he leaves, Simba turns to find Sora, Donald, Goofy, Timon, and Pumbaa watching eagerly, and asks them for help in returning to reclaim his destiny.
The group arrives at the Pride Lands where Simba confronts Scar, demanding he step down. However, Scar manipulates Simba into confessing to Mufasa's murder; but when he has him at his mercy, he confesses that he killed Mufasa. Simba forces Scar to publicly confess. The hyenas attack to buy Scar time to flee, but Sora's group battles the hyenas to give Simba time to chase down Scar. Timon and Pumbaa arrive, but are quickly chased into the king's den by the hyena horde. After Sora, Donald, and Goofy rescue them, they race to the peak of Pride Rock where Simba is fighting Scar. Donald tries to help, but Sora insists that this is Simba's fight. Simba is soon able to flip Scar off of Pride Rock to his death.
... however, Pete appears and insists that it's not over - punctuated by Scar somehow pulling himself back up from the cliff. Pete explains that Scar's anger and jealousy turned him into a powerful Heartless, who will rule the future Pride Lands of Darkness. Sora, Simba, Donald, and Goofy face off with the tyrant, and are able to defeat him, the darkness leaving Scar's body a lifeless corpse.
Sometime later, Simba ascends the throne of Pride Rock and becomes king. Mufasa's ghost appears once more, and Sora sees the opportunity to open a new gateway. Sora explains to Timon and Pumbaa that they have to leave, and Timon and Pumbaa worry that Simba will forget to tell the other carnivores they're his friends. Sora laughs and remains adamant that you can't forget your true friends as they leave the Pride Lands.
- Accidental Hero: Scar accidently saves Sora from being eaten when he roars in anger to summon the hyenas to Pride Rock. Banzai lampshades the bad timing.
- I'm a Humanitarian: Lionitarian in this case, but Scar orders his subjects to eat Sora for trespassing. Truth in Television; prides are known to kill outsiders, and there have been reports of lion cubs being eaten.
- Let's Meet the Meat: The hyenas offer to let Sora and his friends stick around for lunch. Of course, in this world, they're the lunch.
- P.O.V. Sequel: The first half of the episode shows the middle of the film's events from Nala's point of view, albeit with the reason of her exile being different from "The Madness of King Scar".
- Not His Sled: Instead of being Eaten Alive by the hyenas, Scar climbs back onto Pride Rock's summit as a Heartless. In fact, he's one of only two beings in the whole franchise (the other being Terra-Xehanort) to retain his original form as a Heartless. The second visit makes him a Satanic Archetype, too.
- R-Rated Opening: The episode begins with Mufasa's death in a flashback, and the first scene with Sora has him almost eaten alive by the hyenas.
- The Usurper: Nala hopes Sora can overthrow Scar, even if he shows opposition to "going around knocking kings off their thrones". Her hopes are quashed when Rafiki points out that Sora is not fit for the role.