The lava-covered Heatran continues its ascent along Mount Coronet, observed by Ash, his friends, and Team Galactic as they try to withstand the intense heat it gives off. The lake guardians use their powers to look inside the lava monster, seeing the real Heatran and the Flame Plate trapped inside. Heatran lets out a fierce roar, which causes the space-time gate in the sky to react. While Ash and his friends try to figure out what is going on with it, they are suddenly given a vision by the lake guardians, showing them what they just saw inside Heatran. Seeing this vision, Brock understands that the fiery monster is actually a fiery clump of energy, while the real Heatran is trapped inside it.
The Team Galactic Commanders attack the lake guardians to keep them from interfering, although the Legendary Pokémon are able to defend themselves. Goh demands to know what Team Galactic did to Heatran, but Mars says that the Flame Plate is the true cause for its current situation. The Plate is trying to return to the heavens where it came from, and is thus driving Heatran towards the summit, causing the space-time gate to open in the process. This fits Team Galactic's needs, however, as it will allow them to bring back their leader, Cyrus, who had once disappeared into a space-time gate. The Commanders then decide to eliminate the group, while Ash and his friends swear to protect the Pokémon whose homes are being destroyed by Team Galactic's selfish actions. While the Commanders intend to keep the group occupied to secure Heatran's path, after the two sides exchange a few attacks, Brock urges the others to go ahead while he keeps Team Galactic occupied. They agree, and Brock calls out Steelix and Blissey to join Croagunk in battling the Commanders.
Ash, Dawn, and Goh decide to use Water attacks to stop Heatran, with Ash also requesting help from the lake guardians' Psychic powers. Ash has his Dracovish use Water Gun, Goh tells Inteleon to use Snipe Shot, and Dawn's Piplup uses Whirlpool. The lake guardians use Psychic to combine the moves into a single giant sphere of water, which makes a direct hit on Heatran. However, the heat it's giving off is so intense that even this combination attack has no effect on it.
At the fight against the Commanders, Brock suddenly receives reinforcements in the form of Cynthia and her Garchomp. She tells Brock that Heatran can be stopped by collapsing the ground under it to make it lose its footing and tells him to take her Garchomp to go assist in doing so. Brock's Croagunk and Blissey wish to stay behind, and he respects their wish before having Steelix use Dig to create a tunnel, leaving with Garchomp as Cynthia calls out her Roserade to join Brock's Pokémon.
Brock quickly reunites with his friends and relays Cynthia's strategy to them. After the lake guardians stop Heatran with their Psybeams, Steelix and Garchomp begin executing the plan by using Dig to weaken the ground underneath Heatran. Next, Pikachu uses Iron Tail to create cracks on the ground, which Goh's Cinderace strikes with Pyro Ball, breaking them further apart. As a finishing blow, Dawn calls out her Mamoswine and has it use Ancient Power, completely collapsing the ground underneath Heatran and trapping it. Distracted by the sounds above them, the Team Galactic Commanders suddenly find their Pokémon pummeled into submission by Cynthia's Roserade's Petal Blizzard.
Just as the situation seems to be getting under control, bolts of energy strike down on Heatran, causing it to erupt with even more fire energy and release a beam that fully opens the space-time gate. Seeing their chance to get Cyrus back, the Commanders retreat with their helicopter, covering their escape with Jupiter's Skuntank's Smokescreen. As Heatran reemerges from the pit it was momentarily trapped in, now even bigger than before, Ash and his friends also decide to retreat, heading for the summit. Goh theorizes that Heatran's growth is probably a cause of it absorbing energy from the space-time gate. Brock agrees, adding that the energy has also amplified the pressure inside Heatran, threatening to cause an explosion that would obliterate not only the entire Mount Coronet, but them and the real Heatran with it.
The group reaches the Spear Pillar at the summit ahead of Heatran, but still have no method of stopping the imminent explosion. Suddenly, Arceus appears above the mountain, catching everyone's attention as the Alpha Pokémon unleashes its Judgment.