Pokémon Hunter J arrives in Snowpoint City and targets the Legendary Pokémon Regigigas which is sleeping inside the Snowpoint Temple. After J commands her henchmen to launch an attack, a maiden from the shrine asks Ash and his friends for help. But Ash and the others come too late: Regigigas has been reawakened and starts rampaging!
Maria and Samuel report that some people came in the Snowpoint Temple and have sealed it. Though now knowing who these people are, Brandon tells them they need to go. The heroes offer help and board the Battle Pyramid. Team Rocket has heard of this and also board the ship (secretly). Brandon asks Ash if he knows of the legend of the temple. Ash does not, so Maria tells him. A volcano erupted and caused lava to melt everything. However, Regice, Regirock, Registeel and Regigigas have stopped the lava from penetrating any further, thus saving the City. Regigigas was sealed as a stone to protect the temple, while Regice, Registeel and Regirock are now the guardians.
Brandon thinks these men are after Regigigas. Samuel got a contact and displays what is happening. Ash recognizes the woman to be Hunter J, who is after Regigigas. Dawn tells that Regigigas is a legend, per Brandon's words, but Brandon replies that it is not a legend, as he came to investigate. Team Rocket heard this and are happy to know they might get a chance to get Regigigas, but fall down from the Pyramid. When seeing the Battle Pyramid flying over, J's men inform her Brandon is here. J orders them to distract them. Skarmory and Metang hamper the Battle Pyramid's way, using Flash Cannon and Sludge Bomb to attack it. They land abruptly after taking so much damage, so Samuel goes to repair the motors while the rest go towards the temple in a mini-craft. Pikachu uses Thunderbolt and Piplup BubbleBeam to hit Skarmory and Metang.
The mini-craft lands and everyone goes in the temple. J has reached the end and sees the pillars of steel, ice and rock. She sends Salamence, who uses Hyper Beam. Destroying two pillars, it goes to destroy the last one, but Brandon stops them. Salamence uses Hyper Beam and makes the last pillar fall down. The orb glows, but it does not awake Regigigas. Salamence uses Flamethrower, causing a strange magic to be turned on, as the mighty Regigigas appears. Regigigas is very angry and uses Hyper Beam and destroying everything, even if Ash tries to calm it down.
J is about to capture Regigigas, though Regigigas uses Hyper Beam. Salamence counters with Dragon Pulse, but gets pushed away. Regigigas uses Hyper Beam even more, so J retreats, while Brandon brings Regirock, Regice and Registeel to destroy the rocks while the heroes, Maria and Brandon go out of the temple. Regigigas' Hyper Beam causes the heroes to be sent away out of the temple. After the smoke clears, they see Regigigas is amidst the rubble of the temple, but it breaks free, causing even more damage.
Brandon has the idea of catching it. His Pokémon use Hyper Beam, causing a collision with Regigigas' Hyper Beam. So, they use Focus Punch, but it stops them using Hammer Arm with one hit. Regirock and Registeel hold Regigigas, while Regice uses Ice Beam to freeze them. J plans to let them exhaust Regigigas, while she can go get it. Regigigas breaks free and Regice uses Zap Cannon, while Registeel Iron Head and Regirock Stone Edge, which wound Regigigas. Brandon is about to catch Regigigas, though Ariados used String Shot to bind them. J is about to get Regigigas, however Regigias' Confuse Ray causes Regirock, Regice and Registeel to be on its side. They attack Salamance and J. They go on a rampage, so Brandon calls his Pokémon back, but for some reason, they do not and Regice uses Zap Cannon against him. They watch as they go towards the city.
Team Rocket sees the rampage and plan to get Regigigas, but get blasted off by Flash Cannon. As they try to free themselves, Brock flirts with Maria, which causes him to be attacked by Croagunk. Fortunately, this causes the String Shot to be cut. Brandon tells Samuel to report to Jenny what happened while they go to stop Regigigas. J and her men are ready to assault Regigigas. They come and use Hyper Beam, but the air ship's beam causes the Hyper Beam to be negated and put Regigigas in ground. They fire a liquid which causes Regigigas to be bound, which also causes Confuse Ray to wear off. Nevertheless, Regigigas uses Hyper Beam on the air ship, causing damage to it, so the airship goes invisible.
Though not controlled, Regirock, Regice and Registeel use Hyper Beam to attack J and Salamence, but they evade. J fires a beam to capture Regigigas, but Regirock stands in the way and gets captured instead. The heroes arrive and watch as Regice and Registeel get captured as well, trying to protect Regigigas. They see Regigigas is much less angry. J fires another beam, but Brandon jumps and gets captured as well. J goes to fire the beam, but Pikachu's Thunderbolt and Piplup's BubbleBeam cause her not to fire, so Salamance uses Dragon Rage. Regigigas is free and protects the heroes, causing Dragon Rage to backfire. One shot causes J's device to be destroyed. J orders her men to attack, but to her displeasure, her men tell her contractors have run off with all the trouble. J and her men retreat, leaving Brandon and his Pokémon captured.
Dawn asks Brock if there is a way to return them back, but Brock does not know. Maria asks of Regigigas to help them as they saved it. Regigigas' aura shines bright, using Hidden Power and it restores them. Maria tells Brandon he saved Regigigas, so Brandon thanks it. Regigigas returns into the orb form, as it goes back to sleep. Brandon promises to defend its life. Brandon places the orb where it was and promises to re-build the temple. He asks Maria to help him, which she agrees to and his Pokémon will help him in this task. The heroes watch the orb and hope that it is not disturbed again.
- Professor Oak's Pokémon lecture: Magneton
- This is the first time a human, Brandon, is turned into a stone by J's bracelet.
- This is, however, only the second time when a human has been turned into a stone in the anime. The first time was when Ash was turned into a stone in Mewtwo Strikes Back.
- This is the first appearance of J's Ariados since its debut.
- This episode features four legendary Pokémon (Registeel, Regirock, Regice, and Regigigas), more than in any prior episode. However, the record is broken only 23 episodes later.
- This is also the first episode to feature a legendary trio and their master in the same episode.
- Music from Destiny Deoxys is used as background music.
- Team Rocket doesn't recite their motto in this episode.
- When Regirock and Brandon were petrified by J, there are inconsistencies with their body positions.
- Regigigas uses Hammer Arm during this episode, a move it cannot legally learn.