Plot
On planet Saharu, Gopal and BoBoiBoy retrieve a Power Sphere from a penguin monster's nest. Gopal drops one of its eggs, provoking the monster. Adu Du and Probe snatch the Power Sphere, forcing Fang and Yaya to intervene. Before leaving, BoBoiBoy rescues Adu Du and Probe.
In space, crystal miners discover Retak'ka – the first elemental master who was sealed 100 years earlier by Hang Kasa – within an asteroid. Granted leave, BoBoiBoy and his friends drop by Tok Aba's Kokotiam. Papa Zola meets his daughter with Mama Zila, Pipi Zola.
Retak'ka escapes with a fragment of his powers, threatening the miners to take him to TAPOPS. BoBoiBoy invites Fang for dinner at Aba's home, while Zola and Gopal take Pipi on their spaceship to show her EggaBot, which Pipi activates to prevent Adu Du and Probe from stealing it.
When Retak'ka attacks TAPOPS Station, Koko Ci sends the group an emergency message with coordinates to planet Quabaq. Wishing to help Koko Ci, BoBoiBoy has OchoBot teleport to the station. There, Retak'ka demands BoBoiBoy to return him his powers, defeats Fang, Yaya, Ying, and drains BoBoiBoy's Solar, Thunderstorm, Cyclone and Thorn elements. Gopal rescues BoBoiBoy while Koko Ci tells them to save themselves and find Kasa. Zola teleports them to Quabaq, crashing by wetlands. The miners then detonate explosives placed around the station.
On Quabaq, BoBoiBoy and OchoBot download Koko Ci's message – damaged in the crash – before evacuating with Gopal and the Zolas. Encountering Kang Kongs – sloth-like monsters sensitive towards light – BoBoiBoy distracts them with Blaze since Retak'ka stole his Solar element, but runs out of energy before Kasa rescues them. The next morning, Kasa offers to train them against Retak'ka, his former friend.
Retak'ka drains planet Gur'Latan, massacring all its soldiers. Having rescued everyone left on TAPOPS Station, Captain Kaizo investigates Gur'Latan with Fang, determining Retak'ka drained other planets' energies to upgrade his powers. Tracking Retak'ka to Bayugan, Ying warns its inhabitants. On route to planet Rimbara, the miners receive BoBoiBoy's location on Quabaq; Kaizo's group evacuate Rimbara's Cendawa tribe as Retak'ka drains the planet. Maskmana deploys ArmoBot for Fang, Yaya and Ying to hold off Retak'ka.
As BoBoiBoy and Gopal finish training, the Zolas explore Kasa's house filled with technology. Kasa then forces BoBoiBoy and Gopal to pay for training. They have insufficient money, so Kasa traps them in crystal and claims BoBoiBoy's Quake power. Pipi presents OchoBot who powered Kasa's house, assuming Kasa lied to them. Kasa then introduces as the master of the Crystal element and plays the repaired message on OchoBot, proving Koko Ci did not tell them to train under Kasa. BoBoiBoy tells Kasa to share his story with Retak'ka – they met on planet Gugura – a large garbage dump – where they found elemental Power Spheres. Retak'ka greedily stole five more elements and coveted Kasa's Crystal power, thus Kasa drained his elements using OchoBot.
Retak'ka has Kasa meet him on Earth – informed it has seven elements – knowing that Kasa tried to lure him to Quabaq, having captured Fang, Ying and Yaya. Pipi frees them with EggaBot, allowing BoBoiBoy to join the fight. Kasa saves BoBoiBoy from being smashed by Retak'ka and apologises for taking his Quake element – telling him to reclaim the others – before Retak'ka drains Kasa’s Crystal element. The Zolas, Adu Du and Probe defeat the miners, freeing Fang, Yaya and Ying.
Realising 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 freezes Retak'ka, drains his 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 set up at the dam with their families, while the rescued Cendawa tribe oversee Earth's rebuilding. A surviving Kasa acknowledges BoBoiBoy as the new master of the elements.
In a post-credits scene, Maskmana gives ArmoBot to BoBoiBoy‘s father Amato for repair.
