500 years ago, Kumandra, a prosperous land where humans lived alongside dragons, was ravaged by the Druun, mindless spirits that turn every living thing in their path to stone. Sisu, the last surviving dragon, concentrated her magic into a gem and blasted away the Druun, reviving Kumandra's people but not its dragons. A power struggle for the gem divided Kumandra's people into five chiefdoms called Fang, Heart, Spine, Talon, and Tail, corresponding to their placement along a gigantic dragon-shaped river. In the present, Chief Benja of the Heart tribe retains possession of the gem and trains his young daughter Raya, a warrior princess, to protect it. Benja, believing Kumandra can be reunited, holds a feast for all five tribes. During the feast, Raya befriends Namaari, princess of the Fang tribe, who gives Raya a dragon pendant. Raya trusts Namaari and shows her the gem's chamber but Namaari betrays her as part of a plot to help Fang steal the gem. After being alerted to the attack, Benja and the other tribes arrive and start fighting over the gem, breaking it into five pieces. The gem's destruction creates a fissure that releases the Druun, who quickly take over the Land of Heart. The tribe leaders each steal a piece of the gem and flee. Benja notices water repels the Druun and saves Raya's life by throwing her into the river before being turned to stone. Six years later, Raya treks across Kumandra to find Sisu, hoping she will create another gem and banish the Druun. In Tail, Raya summons Sisu, who says she did not create the gem but wielded it on behalf of her four siblings, all of whom contributed their magic to the gem. Raya and Sisu resolve to reclaim the four pieces of the gem, reassemble it, and use it to banish the Druun and restore those who were turned to stone, while making new friends; including Boun, a young restaurateur from Tail; Little Noi, a baby con artist from Talon; and Tong, a warrior from Spine; all of whom have lost loved ones to the Druun. Namaari, hoping to gain the gem shards for the Fang tribe, pursues Raya. Since each gem shard they acquire blesses Sisu with one of her siblings' magical powers, Raya, who does not fully trust their new companions, insists Sisu remain disguised as a human but in Spine, Sisu reveals herself to save Raya from Namaari. In Fang, Sisu persuades Raya to propose an alliance with Namaari rather than steal the final shard. As a gesture of trust, Raya returns the pendant Namaari gave her years before. Namaari, torn between her responsibility to Fang and her wish to help defeat the Druun, threatens the party with a crossbow. Sisu tries to calm Namaari down but Raya attacks with her whip sword after seeing Namaari's finger on the trigger, causing the crossbow to fire and kill Sisu. Sisu's death drains away all of the water, allowing the Drunn to overrun the realm. Furious by Namaari’s actions, Raya pursues her and finds her grieving the petrification of her mother Chief Virana. Namaari and Raya fight while Raya's companions use the gem pieces to evacuate the people of Fang. Raya prepares to kill Namaari but stops when Namaari reminds her that her inability to trust others led to Sisu’s death, and they go to aid the others. As the Druun gain on her group, Raya remembers how trust allowed Sisu to save the world. She urges the others to unite and reassemble the gem, showing her faith in Namaari by handing over her gem piece and allowing the Druun to turn her into stone. Boun, Tong, Noi, and the ongis follow suit, and Namaari reassembles the gem before also being petrified. This unleashes a shockwave that spreads throughout Kumandra, vanquishing the Druun and conjuring up a magical rainstorm that revives everyone, including the dragons who later revive Sisu. After the group reunites with their loved ones, the tribes and dragons gather at Heart to unite as Kumandra once again.
