Plot
On planet Saharu, Gopal and BoBoiBoy retrieve a Power Sphere, EggaBot, from a penguin monster's nest. Gopal drops one of its eggs, awakening the monster. Adu Du and Probe snatch the Power Sphere, forcing Fang and Yaya to intervene. Before returning, BoBoiBoy rescues Adu Du and Probe.
In space, crystal miners discover Retak'ka—the first elemental master sealed 100 years earlier—within an asteroid. Granted leave for completing all missions, the MYS Kebenaran crew drop by Tok Aba's Kokotiam, meeting their relatives, including Papa Zola's daughter Pipi Zola.
Retak'ka escapes with a fragment of his powers, threatening the miners to take him to TAPOPS. Meanwhile, BoBoiBoy invites Fang for dinner at Aba's home, while Papa and Gopal take Pipi on the Kebenaran to show her EggaBot, which Pipi activates, preventing its theft by Adu Du and Probe.
While Retak'ka attacks TAPOPS Station, Koko Ci sends an emergency message with coordinates to planet Quabaq. Prompted to save him, BoBoiBoy has OchoBot teleport the Kebenaran to the station. There, Retak'ka demands BoBoiBoy to return him his powers and defeats Fang, Yaya, and Ying. He drains BoBoiBoy's Solar, Thunderstorm, Cyclone and Thorn elements. Gopal rappels to rescue BoBoiBoy while Koko Ci tells them to save themselves and find Hang Kasa. Papa teleports the Kebenaran to Quabaq, crashing on caustic wetlands. The miners detonate explosives placed around the TAPOPS station.
On Quabaq, BoBoiBoy and OchoBot download Koko Ci's message, damaged in the crash, before evacuating with Gopal and Papa, who inadvertently brought Pipi, while Adu Du and Probe have escaped. Encountering Kang Kongs—sloth monsters sensitive towards light—BoBoiBoy distracts them with Blaze since Retak'ka stole his Solar element. Kasa rescues the group, and next morning, he offers to train them against his former friend Retak'ka.
Retak'ka drains planet Gur'Latan, massacring all its soldiers. Having rescued everyone left on TAPOPS Station, Captain Kaizo investigates Gur'Latan with Fang, discovering that Retak'ka drained other planets' energies to upgrade his powers. Tracking Retak'ka to Bayugan, Ying warns its inhabitants. The miners receive BoBoiBoy's location on Quabaq before heading to planet Rimbara. After evacuating Rimbara's Cendawa tribe aliens, Maskmana deploys ArmoBot for Fang, Yaya and Ying to battle Retak'ka as he drains the planet.
As BoBoiBoy and Gopal finish training, the Zolas explore Kasa's house filled with technology. Kasa forces BoBoiBoy and Gopal to pay for training. They have insufficient money, so Kasa traps them in crystal and obtains Quake from BoBoiBoy. Pipi assumes Kasa lied as Papa witnessed OchoBot being used to power Kasa's house. Kasa refutes, introducing as the master of the Crystal element. He plays the repaired message on OchoBot, proving Koko Ci did not tell BoBoiBoy to train under Kasa. BoBoiBoy has Kasa explain his story with Retak'ka: they met on planet Gugura—a large landfill—where they found elemental Power Spheres. Retak'ka greedily stole five more elements and lusted Kasa's Crystal power, thus Kasa drained his elements using OchoBot.
Realising Kasa baited him to Quabaq with BoBoiBoy's location, Retak'ka has Kasa duel him on Earth, informed by Fang, Ying and Yaya it has the seven required elements. Pipi frees BoBoiBoy and Gopal using EggaBot before fully charging, allowing BoBoiBoy to battle Retak'ka. Kasa intercepts Retak'ka from smashing BoBoiBoy and apologises for taking his Quake element, telling BoBoiBoy to reclaim the others before Retak'ka drains Crystal from Kasa. The Zolas, Adu Du and Probe defeat the miners, freeing Fang, Yaya and Ying.
Remembering splitting makes him weaker, BoBoiBoy fuses his remaining elements Ice and Blaze, creating FrostFire. Gopal throws OchoBot at BoBoiBoy, allowing him to drain Retak'ka's Crystal power. Overpowered by Fang, Yaya and Ying, Retak'ka explodes a nearby dam. BoBoiBoy drains Retak'ka's remaining elements and launches him into space before falling into the river exhausted, prompting his friends to rescue him. The group recuperate at a field hospital near the river with their families, while the rescued Cendawa tribe oversee Earth's rebuilding. Kasa acknowledges BoBoiBoy as the new master of the elements.
In a post-credits scene, Maskmana gives ArmoBot to BoBoiBoy's father Amato for diagnostics, believing Amato should be helping BoBoiBoy.
