There's only a short amount of time left before the Pokémon League. Ash and Brock are watching TV. Bruno has just sent out his Hitmonchan. Suddenly, Misty turns the TV off. She tells Ash that he has to stop goofing off and start training. Brock says that they were watching TV because he wanted to learn the secrets of Pokémon. Ash agrees, but he doesn't know what the secrets are. Ash wishes that he could meet Bruno. Mrs. Ketchum tells the group that there's a rumor going on that Bruno is training at Mount Hideaway.

Misty sees that Mount Hideaway is about seven or eight miles away. Ash and Brock are exhausted from the long walk, but Misty isn't tired at all. Misty gives up and decides to stop for a rest too. They walk to an old lady's house tired and hungry. The old lady brings them something to drink. Ash asks if she knows anything about Bruno. She thinks the Pokémon are always stealing her food. When the old lady looks down at the plate, her food is missing. Ash, Misty, and Brock have eaten her food. Up ahead, the old lady sees the poachers. She runs up towards them. The poachers turns around, and they happen to be Team Rocket. Meowth presses a button, and the motto is fastforwarded. After the motto, Jessie complains that her mouth hurts, and James thinks that he bit his tongue. Team Rocket has decided to do something different since they always lose to Ash and co. They took the old lady's food instead. Angry at Team Rocket, the old lady whacks Team Rocket with her broom. Team Rocket is scared off, and the old lady gets her food back. The old lady asks if Ash and co. are heading up the mountains. When they say yes, she tells them about a giant Onix.

Ash and co. continues to walk up the mountain. Ash points to a strange road below. Brock says that it isn't a road, but tracks left by something really big. Suddenly, the ground starts to shake. In the distance is a giant Onix coming their way. Ash and co. makes a run for it. A man shouts out to Ash and co. to come by him. They dodge the Onix just in time. The man asks if they are all right. Ash and Brock both look up to him, and they recognize him as Bruno. They stare in amazement. They follow Bruno around. Bruno asks them why they are following him. Brock bows down and tells him that Ash needs helping training for the Pokémon League. Ash bows them and pleads for Bruno's help. Bruno agrees to help but only if Ash and Brock does everything he tells them to do.

By the riverside, Ash and Brock are filling buckets with water. The buckets are heavy, and they have to carry them. This will help Ash's phsyical strength and balance. Ash falls over, and the water sprays on Misty's face. Ash's next task is to split wood. This will help Ash grip things better. Ash lifts up the heavy hammer and chops the wood in half. The pieces end up flying into Misty's face. The next task that Ash has to do is lift stones up the mountain. Ash grabs onto a stone, but he loses balance and ends up falling over by Misty. Next, Ash has to peel the bark off a twig. Bruno smiles and tells them that if they ever have to go camping, bring a fork. The twig happens to be the fork. Bruno splits the twig into two pieces, and he uses them as chopsticks to eat food. Ash and Misty don't think that Bruno knows what he is doing. Brock can't believe that Ash and Misty are doubting Bruno. He says that Bruno will act fast if a stick is hurled at him. Unfortunately, Bruno doesn't react at all, and he ends up getting hit by Brock's attack.

When Bruno recovers, Bruno tells them that there is no secret to Pokémon. The only reason he came up the mountains was to capture the Onix. Brock is very disappointed. Team Rocket are spying on Ash and co. from above. They think that all they have to do is capture the strongest Onix and they will become strong.

Team Rocket walks on the track made by the Onix. They think that the only way to capture the Onix is to surprise it. Jessie and James pulls out a gun. They anxiously wait for the Onix to appear. The Onix appears seconds later out of the ground. Team Rocket is scared, but Jessie still wants to capture the Onix.

Ash and co. are walking along the path. Brock thinks that he doesn't want to tell the trainers his secret, but Misty disagrees. They hear a sound and think there's trouble ahead. The sound came from Team Rocket's gun. They successfully hit the Onix, but no damage occurs. The Onix begins to chase Team Rocket. Team Rocket finds a cavern, and they run inside it. The Onix starts to destroy the cavern. Meanwhile, Ash and co. have arrived at the scene. They decide to help Team Rocket. Brock sends out Onix, Misty sends out Staryu, and Ash sends out Squirtle. Brock's Onix tackles the Onix, but it fails to do any damage because the other Onix is bigger than Brock's. Team Rocket is being sealed in. They plea for someone to help them. Squirtle and Staryu uses Water Gun on Onix. The attack does some damage, but the Onix manages to recover. Team Rocket escapes the cavern before it collapsed. With a tail slam, Onix hits Ash and co.'s Pokémon and Team Rocket. Team Rocket blasts off again.

Onix sees Ash and co. on the cliff. It slams into the cliff causing Ash to fall down. Ash stares into the eyes of the Onix. Pikachu comes down and uses Thunderbolt on Onix. Ash reminds Pikachu that electric attacks won't work on Onix. Then Onix attacks Ash. Just before the attack can hit him, Bruno comes down and brings Ash to safety. Ash thanks Bruno for saving him. Misty and Brock joins up with Ash. Bruno tells them to recall back their Pokémon. They follow his orders. Ash, Misty, and Brock wonders what Pokémon and attack Bruno will use on the Onix. Bruno tells them that he will not use a Pokémon. Bruno jumps down, and he asks the Onix the reason it is attacking him. All Onix does is unleash attacks at Bruno, but they all miss him. Bruno jumps onto Onix's head. Onix tries to shake Bruno off but it can't. So Onix attacks with its tail, but Bruno dodges and the Onix hits its own head. Bruno tells Onix not to fear him. He closes his eyes to find out what the Onix is feeling right now. Bruno opens his eyes, and he begins to feel around the Onix. Bruno finds the problem. He reaches in the Onix's body and pulls out a Sandslash. He lets Sandslash out into the wild. Then Bruno throws a Pokéball and captures the Onix.

Ash and co. rejoins with Bruno. The want Bruno to tell his secret. Bruno tells them that humans and Pokémon must live together and care for each other just like Ash and Pikachu. Then Bruno leaves. Meanwhile, Team Rocket somehow has fallen in an Onix's territory. Many Onix surrounds Team Rocket.

English Official Summary

With only three weeks left before the Pokémon League competition, Ash, Brock and Misty head up to Mt. Hideaway to find one of the Elite Four Trainers. Ash and Brock hope he will teach them the real secrets of Pokémon training, but what they really learn is that Mt. Hideaway is the land of overgrown Onix!

Italian Official Summary

Mancano tre settimane all'inizio della Lega Pokémon e i nostri eroi si dirigono verso il Monte Hideaway alla ricerca di uno dei Superquattro per chiedergli dei consigli per l'allenamento ma finiscono invece per imbattersi in degli Onix giganti!

Portuguese Official Summary

A apenas três semanas da competição da Liga Pokémon, Ash, Brock e Misty vão para o Monte Esconderijo para encontrarem um dos da Elite Quatro. Eles querem dicas de treino de Pokémon, mas encontram é uma terra de Onix enormes!

Spanish Latin America Official Summary

A sólo tres semanas de iniciar la Liga Pokémon, Ash, Brock y Misty se dirigen al Monte Hideaway a buscar a uno de Élite 4. Buscan consejos de entrenamiento Pokémon, ¡pero descubren una tierra de enormes Onix en su lugar!

Spanish Official Summary

Cuando solo quedan tres semanas para el concurso de la Liga Pokémon, Ash, Brock y Misty se dirigen a Monte Escondite para ver a uno de los Entrenadores de Alto Mando.

English Great Britian Official Summary

With only three weeks left before the Pokémon League competition, Ash, Brock and Misty head up to Mt. Hideaway to find one of the Elite Four Trainers. Ash and Brock hope he will teach them the real secrets of Pokémon training, but what they really learn is that Mt. Hideaway is the land of overgrown Onix!

Dutch Official Summary

De Pokémon League begint al over drie weken, dus gaan Ash, Brock en Misty naar Mt. Hideaway op zoek naar iemand van de Elite Vier. Ze willen graag Pokémon training tips krijgen, maar ontdekken daarentegen een land vol Onix!

French Official Summary

Il ne reste plus que trois semaines avant la compétition de la Ligue Pokémon. Sacha, Pierre et Ondine se dirigent vers le Mont Cachetou pour y retrouver l'un des Dresseurs de l'Élite des quatre.

German Official Summary

Es sind nur noch drei Wochen bis zum Pokémon-Liga-Wettbewerb. Ash, Rocko und Misty sind unterwegs nach Mount Hideaway, um einen der legendärenTop Vier Trainer aufzusuchen.

Danish Official Summary

Da der kun er tre uger til Pokémon Ligakonkurrencen, tager Ash, Brock og Misty op på Hideaway-bjerget for at finde en fra Elite Four. De kom for at få træningstips, men opdager i stedet et land for forvoksede Onix!