The film opens where the previous film ended, set a few years later as Rafiki (Robert Guillaume) gathers the animals of the Pride Lands together for the presentation of Simba (Matthew Broderick) and Nala's (Moira Kelly) new daughter, Kiara. Mufasa's spirit (James Earl Jones) watches over the ceremony and blesses the cub in a beam of light.Kiara (Michelle Horn) grows into a headstrong, yet stubborn, cub; traits that Simba finds disconcerting as he's worried about the kind of trouble she can get into. Despite Nala's assurances, and Kiara's verbatim recital of every danger to be wary of, Simba assigns Timon and Pumbaa (Nathan Lane and Ernie Sabella) to watch over her. When Kiara discovers the bumbling duo following her, she angrily abandons them and runs off to the forbidden Outlands, a territory inhabited by Outsiders: lionesses banished for having supported Scar while he was king. Just past the border, Kiara bumps into and meets a young cub named Kovu (Ryan O'Donohue). Though they are hostile to each other at first, they quickly become friends (especially after saving each other from a group of hungry crocodiles). They make it to safety in the Pride Lands, unaware that Zira (Suzanne Pleshette), Kovu's mother and leader of the Outsiders, is watching nearby. When Simba and his pride come to retrieve Kiara, he is confronted by Zira. She is quick to remind him of the injustices suffered by her tribe, since the Outlands are a barren wasteland. She introduces Simba to her cub and claims that he, as the last born, was hand-chosen by Scar to be his heir. Though Simba is angered by this, he does not retaliate and demands that Zira leave. The lions depart to their respective domains and Kiara and Kovu say sad farewells to each other.Later, Simba scolds Kiara for disobeying him and says, as future queen, she will need to be wiser. Kiara doesn't like the idea of being queen since the title is only a part of who she is. Simba tells her it's in her blood and that they, like the Circle of Life, are connected to each other; they are one. Meanwhile, in the Outlands, Nuka (Andy Dick), Kovu's older brother, complains to young Vitani (Lacey Chabert) about Kovu being the 'Chosen One', saying he should have been given the role since he's older and Kovu isn't even Scar's son. Vitani rebukes her erratic brother's complaints, implying he's too cowardly to make the claim to Zira herself. At that moment, Zira arrives with Kovu and rounds on Nuka for failing to watch him. Then, she turns to Kovu, reminding him that Simba is the reason for their banishment and Scar's death. However, Kovu expresses the desire to be friends with Kiara. Zira laughs this off, until she hatches an inspirational idea: to use Kiara and Kovu's friendship against Simba. She brings Kovu home to a massive termite mound and announces that his training will henceforth intensify.Years later, Kiara (Neve Campbell), now a young adult, is about to embark on her first solo hunt. Simba, still apprehensive about his daughter's safety and despite his promise otherwise, once again sends Timon and Pumbaa to supervise her. When Kiara discovers she is once again being followed, she gets angry and runs away. Meanwhile, Zira implements her plan to infiltrate Simba's pride and sends Nuka and Vitani (Jennifer Lien) to ignite a wildfire on the plains. Kiara becomes trapped by flames and smoke and faints. Kovu (Jason Marsden) then appears and carries Kiara to safety. Zazu (Edward Hibbert) sees this and reports to Simba who has, by now, seen the smoke from Pride Rock. Simba and the pride locate Kiara, and Kovu makes a plea to join them. He claims he left the Outsiders and requests to be judged for who he is now rather than by association. Simba agrees only to repay the debt owed for saving Kiara's life and promises to enforce judgment soon. At Pride Rock, he forces Kovu to sleep outside. Kiara thanks Kovu for saving her, but he criticizes her hunting abilities. So, Kiara requests that he teach her better, starting at dawn. That night, Simba suffers a nightmare where he relives his father's death at the hands of Scar, before Scar morphs into Kovu, sending Simba to his death in turn.The next morning, Simba goes to a watering hole alone, with Kovu close by and ready to pounce. However, Kiara arrives and they go off together. Kiara's hunting skills are still wanting so Kovu offers a demonstration. He pounces over a hill, aiming at some landed birds, but instead comes face to face with Timon and Pumbaa, enjoying a smorgasbord of bugs. However, the birds are hogging the good eats, so Kiara shows Kovu how to roar to chase them off. They all run off in pursuit of the birds, hooting and laughing, which confuses Kovu since he's never had any kind of fun before. Later, Kiara shows Kovu the star-studded night sky and tells him all the great kings of the past are there. Kovu asks if Scar is up there, which leads to an awkward moment where Kovu admits that, while he was not Scar's son, he was still a part of him. The young lions become closer and closer, but Kovu feels conflicted between fulfilling his mission and his growing feelings for Kiara. Before he leaves, Rafiki appears and stops him. Having seen a vision from Mufasa that the two young lions will bring peace between the prides, he takes Kiara and Kovu to a place in the jungle called 'Upendi', a play on the Swahili word for 'love'. There, the two lions fall in love. That night, upon returning to Pride Rock, Simba invites Kovu to sleep inside, deciding to give him a chance. Nearby, Vitani sees Kovu failing to attack Simba and reports this to Zira.In the morning, Simba takes Kovu for a walk and tells him the true story of Scar, which Kovu has never heard. Just as Simba implies he's willing to let Kovu live with in the Pride Lands, Zira and the Outsiders appear and ambush Simba. Kovu tries to intervene but is knocked out. The Outsiders chase Simba into a gorge and he attempts to flee by climbing up a dam made of fallen trees. Nuka rushes forward in a desperate bid to impress his mother and claws at Simba's feet, but he loses his footing and is crushed by trees. Zira comforts Nuka as he dies and rounds on Kovu for failing to act, scarring his face. Kovu flees and returns to Pride Rock where a wounded Simba promptly exiles him and sends Kiara to confinement inside the den. She escapes, however, and is later reunited with Kovu on the plains. Kovu suggests running away together, but Kiara states that, if they leave, their prides will be forever divided.Meanwhile, Zira leads her pride into the Pride Lands in a final bid to claim Pride Rock. Simba and his pride face off with them at the gorge in a torrential downpour and a fierce fight breaks out. Then, as Simba and Zira face off, Kovu and Kiara arrive to stand between them. Kiara tells Simba that he once told her 'we are one' and explains that this applies to all lions, even the Outsiders. Her words inspire everyone, except Zira, who still can't let go of the past. She lunges at Simba, but Kiara intercepts and the two of them tumble down the side of the gorge. Kiara lands on a ledge while Zira hangs on by her claws. In a reversal of roles, Kiara offers help to Zira, but she refuses and falls to her death into the flooded gorge below. Simba leads everyone, Outsiders and Pride Landers alike, back to Pride Rock. The next day, Simba, Nala, Kiara, and Kovu stand on the ledge of Pride Rock and roar together to bring in a new era of peace. From on high, Mufasa looks down with pride and repeats the adage: 'We are one'.