Ash and co. have found a river in Dewford Island. Max thinks that they will find some rare Pokémon if they keep on following the river. Ash likes the "rare Pokémon" part because he can keep up with his training and find some rare Pokémon. They are following the river to find a new training spot. May shapes her hands as a video screen. She is pretending to be a TV Reporter. Suddenly, the group finds their path blocked by a waterfall. Brock thinks that the rare Pokémon are on top of the waterfall. He sends out Lotad. Then Brock takes a rope with a rock on the end of it. He throws it and Lotad uses Water Gun to push the rope around a tree. Afterwards, Ash and co. begin to climb the waterfall using the rope. May is already at the top of the waterfall. She helps pull Ash, Brock, and Max up. Apparently, May used Silcoon's thread to help herself up.

The group notices that the water is much more calm at the top. They continue to walk. Brock notices the ground has gotten to be more muddy. Up ahead lie several Mudkip. Ash looks up Mudkip in his Pokédex. On a rock are two Mudkip that were just born. May remembers her first experience with Mudkip. Now she thinks the Mudkip are cute. Brock explains that Mudkip are rare Pokémon. May wants to capture one. She runs towards the Mudkip. A bigger Mudkip comes out and uses Water Gun on May's face.

Suddenly, one of the baby Mudkip falls in the river. It begins to flow downstream to the main current. Brock sends out Lotad to save the Mudkip. Lotad swims and catches up with the baby Mudkip. However, Lotad is now stuck as it is now floating downstream. The bigger Mudkip from before jumps in the river and pulls Lotad to dry land. Brock walks over to the Mudkip. The Mudkip are bit scared of Brock, but Brock holds out his hand to the Mudkip and assures it that there is nothing to be afraid of. Ash, May, and Max meet up with Brock.

Someone then comes out of the bushes. May at first thinks it's a monster, but Max reassures her that it's a person. The man thinks Ash and co. are stealing the Mudkip. Ash tells the man that they would never steal the Mudkip. They were just saving one of the Mudkip that fell in the river. The man believes Ash's story. Then he introduces himself as Swampy to Ash and co. Swampy wonders how Ash and co. were able to get past the fence. Ash and co. tell him that they took the river entrance up to the place. Then Swampy offers them some tea back at his place.

Swampy says that his place is usually where the Mudkip are raised. Brock sees four blue things and asks Swampy what they are. The blue things happen to be Mudkip eggs. Ash and co. are happy to see the eggs since they never have seen them before. Then they wonder where Swampy gets the eggs from. It is suppose to be a secret, but Swampy his secret to them. Swampy gets the eggs from the Pokémon League and then raises the eggs himself. Brock mentions to Swampy that he is a Pokémon Breeder. Swampy offers Brock a chance to see a Mudkip hatch from its egg.

They go to a nest with three eggs. One of the eggs hatch into a Mudkip. May really thinks the baby Mudkip are cute. Brock tells Swampy that it was actually an older Mudkip that saved his baby Mudkip. Swampy says that the older Mudkip is actually a wild Mudkip who likes to sneak in sometimes and protect the babies, however it is too big for the place. Swampy wants to find a trainer who can take care of the Mudkip, otherwise it won't have any friends.

Team Rocket is walking through the grass. They come across a fence. Meowth wants to know what a fence would be doing in this place. James says that someone obviously doesn't want them trespassing. James thinks someone has something rare and valuable. Team Rocket's eyes light up. Jessie sends out Seviper and James sends out Cacnea. Seviper uses Poison Tail on the fence, but it doesn't break. Cacnea uses Needle Arm, but it uses the attack on James. James slams right through the fence and breaks it.

Swampy hears the alarm sound. They run over to see what happened. Brock sees the Mudkip from before. Brock says hello to the Mudkip, but it runs away. Brock chases after it. Brock follows Mudkip to another part of the forest. Brock wants Mudkip to come with him, but Mudkip still doesn't trust Brock. Brock then holds out some Pokémon food for Mudkip, but Mudkip doesn't eat it.

Ash, May, Max, and Swampy run to the front where the fence is at. They see the fence is totally destroyed. Team Rocket pops out from behind the bushes. They say their motto. Ash tells Swampy that Team Rocket are the bad guys, and that they want to steal the Mudkip. Team Rocket dreams about capturing all of the Mudkip and being executives. Swampy has a problem with being secretive. He always gives out secret information. He accidently tells Team Rocket that by breaking the dam that holds the water will flood the place leaving the Mudkip defenseless. Team Rocket hears this. James sends out Cacnea and tells it to use Needle Arm. Cacnea hits James with Needle Arm. James flies through the dam. The water begins to rush out.

Brock also notices the strong current of water. He sends out Forretress to stop the water from getting any closer. While Forretress is holding back the water, Brock, the bigger Mudkip, and Lotad help rescue the baby Mudkip. When Forretress can't hold back the water anymore, it returns to Brock. Then they all go to higher ground. However, down below is still one more baby Mudkip. The bigger Mudkip jumps into the water to save the baby. It grabs onto the baby, but the Mudkip can't resist the current. It is headed straight for the waterfall. Both Mudkip fall down the waterfall, but the bigger Mudkip is holding onto a rock that is extending out of the waterfall. Brock finds the rope that he used earlier. He ties himself the rope and jumps into the water. Brock holds his hand out to the Mudkip. Mudkip has no choice but to trust Brock. It holds out its fin to Brock. Brock grabs hold onto Mudkip and the baby. Ash and the others pull Brock up.

Suddenly, the group hears a noise coming from the swamp. It is Team Rocket in their new machine. They are searching for the Mudkip. They begin to scoop up the Mudkip and place them in a bag. Ash demands Team Rocket to stop stealing the Mudkip. Brock notices that the feet to Team Rocket's machine is sinking in the ground since the ground is very soft. He tells Lotad and Mudkip to use Water Gun on the ground. This way Team Rocket will get stuck. Mudkip and Lotad obeys Brock's orders. Team Rocket make a joke that the Pokémon are helping them "grow." They suddenly realize that Ash and co. are trying to make them sink. Team Rocket can't move at all. Mudkip then tackles the bag, freeing all the baby Mudkip. Afterwards, Pikachu uses Thunderbolt to blast Team Rocket off in the sky.

Brock thanks Mudkip for doing a good job on saving the baby Mudkip. Ash and the others notice how close Brock and Mudkip have become. Swampy wants Brock to take the Mudkip along with him on his journey. Brock thinks it's a good idea. Brock asks Mudkip if it wants to come with him. Mudkip decides to come with Brock. It happily jumps in Brock's arms. Now that Brock has a new Pokémon, Ash continues his training for his Dewford Gym rematch.

English Official Summary

As our heroes set out on their journey again, they encounter a waterfall. Brock ties a rope to a rock and, with Lotad's help, wraps it on a branch above the waterfall. After Brock helps everyone up the rope, they discover a lake filled with Mudkip. Brock notices a baby being washed away in the current and sends Lotad to help. Lotad gets caught as well and a larger Mudkip jumps in and saves them both. At this point an older man comes out, afraid that Ash and company are trying to steal the Mudkip. They explained what happened and are invited in for lunch. The man explains that he takes care of and raises the Mudkip in the lake. He even shows them a baby Mudkip hatching out of an egg. He explains that while most Mudkip leave to explore the world, the larger one stayed to protect the babies. Throughout lunch, Team Rocket is debating whether or not to enter the lake area. They of course, do so, knocking over some cans that the caretaker had set up as sort of a security system. The man hears the noise and goes to inspect what is going on. Team Rocket destroys the dam so that the Mudkip are washed away and they can catch them easier. Brock uses his Pokémon to save the Mudkip. The larger Mudkip jumps in the water to rescue a baby that was being washed away, only to get caught in the current itself. It clings to a rock on the side of the water fall and finally agrees to let Brock rescue it. Team Rocket arrives again, this time in a robot with scoops for hands, which they use to capture the baby Mudkip. Brock tells Lotad and Mudkip to use Water Gun at the base of the robot, which creates a mud pit and sinks Team Rocket. Pikachu then sends Team Rocket on their way. The show ends with the large Mudkip deciding to leave the lake with Brock.

French Official Summary

Sacha et ses amis suivent une petite rivière, dans l’espoir de découvrir l’endroit idéal sur l’Île de Myokara pour un bon entraînement Pokémon. Après avoir escaladé une cascade, ils se retrouvent dans une zone, interdite aux étrangers, où un vieil homme élève des Gobou du lac. La Team Rocket, qui suit nos héros de près, arrive également au lac et les bandits réfléchissent aux moyens de voler les Gobou. Lorsque le vieillard révèle l’emplacement du barrage qui protège le lac, la Team Rocket passe à l’action. S’apercevant que le barrage peut être facilement détruit, laissant ainsi les Gobou sans défense, ils mettent en branle un plan qui va forcément déclencher une catastrophe !

German Official Summary

Unsere Helden setzen ihre Reise fort und kommen an einen Wasserfall.

Italian Official Summary

I nostri eroi riprendono il viaggio e s'imbattono in una cascata e successivamente in un lago che riserva molte sorprese.

Portuguese Official Summary

Ash e seus amigos encontram um lago cheio de Mudkip e logo se encontram protegendo os Pokémon de um plano da Equipe Rocket!

Spanish Latin America Official Summary

Ash y sus amigos se encuentran con un lago lleno de Mudkip, ¡y pronto acaban protegiendo a los Pokémon de un plan del Equipo Rocket!

Spanish Official Summary

Ash y sus amigos siguen un riachuelo para descubrir el lugar perfecto en Pueblo Azuliza para retomar su entrenamiento Pokémon. Después de subir una cascada, llegan a una zona prohibida para los foráneos en la que un anciano cuida a un Mudkip en el lago. El Team Rocket, siempre pisando los talones a nuestros héroes, también llega al lago y piensa en cómo podría robar al Mudkip. Cuando el hombre revela dónde está la presa que protege el lago, el Team Rocket se pone en marcha. Cuando ven lo fácil que sería destruirla, dejando al Mudkip indefenso, desencadenan un oleaje que solo puede traer una cosa: ¡problemas!

English Great Britian Official Summary

As our heroes set out on their journey again, they encounter a waterfall. Brock ties a rope to a rock and, with Lotad's help, wraps it on a branch above the waterfall. After Brock helps everyone up the rope, they discover a lake filled with Mudkip. Brock notices a baby being washed away in the current and sends Lotad to help. Lotad gets caught as well and a larger Mudkip jumps in and saves them both. At this point an older man comes out, afraid that Ash and company are trying to steal the Mudkip. They explained what happened and are invited in for lunch. The man explains that he takes care of and raises the Mudkip in the lake. He even shows them a baby Mudkip hatching out of an egg. He explains that while most Mudkip leave to explore the world, the larger one stayed to protect the babies. Throughout lunch, Team Rocket is debating whether or not to enter the lake area. They of course, do so, knocking over some cans that the caretaker had set up as sort of a security system. The man hears the noise and goes to inspect what is going on. Team Rocket destroys the dam so that the Mudkip are washed away and they can catch them easier. Brock uses his Pokémon to save the Mudkip. The larger Mudkip jumps in the water to rescue a baby that was being washed away, only to get caught in the current itself. It clings to a rock on the side of the water fall and finally agrees to let Brock rescue it. Team Rocket arrives again, this time in a robot with scoops for hands, which they use to capture the baby Mudkip. Brock tells Lotad and Mudkip to use Water Gun at the base of the robot, which creates a mud pit and sinks Team Rocket. Pikachu then sends Team Rocket on their way. The show ends with the large Mudkip deciding to leave the lake with Brock.

Russian Official Summary

Взобравшись на водопад, Эш и его друзья находят озеро с Мадкипами, которых защищает огромный и бдительный Макдип-одиночка. Их хозяин - старик по имени Свампи, рассказывает, что выращивает Мадкипов из яиц, которые получает из Лиги покемонов. По его словам, самый большой Мадкип - это дикий покемон, который появился в заповеднике и стал помогать приглядывать за остальными. И, конечно, появляется Команда Р, чтобы все разрушить, и ломает преграду, защищающую территорию Мадкипов. Большой Мадкип спасает малыша, но вскоре и ему самому нужна помощь. Брок отважно спускается в водопад и спасает двух Мадкипов. Большой покемон помогает Лотаду Брока одолеть Команду Р, а затем присоединяется к Броку в его путешествии.

Dutch Official Summary

Ash en zijn vrienden komen langs een meer vol met Mudkip, maar moeten al snel deze Pokémon beschermen, omdat Team Rocket iets sluws van plan is!

Danish Official Summary

Ash og hans venner kommer forbi en sø, som er fuld af Mudkip, og snart er de i gang med at beskytte disse Pokémon mod Team Rockets rænkespil!

Swedish Official Summary

Ash och hans vänner kommer till en sjö full av Mudkip och snart är de i full färd med att skydda alla Pokémon från en av Team Rockets onda planer!