May holds her ribbon and Pokémon egg in her arms while Ash trains for his battle at the Battle Dome. Ash has Pikachu practice its Volt Tackle attack. Their training isn't doing so well. Brock, May, and Max think that Ash is training too hard. Max checks his PokeNav and sees that there is a fishing spot nearby.
When they arrive at the lake, they are shocked. The water is a greenish color and nobody is there. Brock wonders if there is anyone at the boathouse. Nobody answers when they call out for someone. Max sees a sign. It says that it's okay to use the fishing rods.
Brock casts his rod into the water. He tells Ash that remaining relax will improve your chances of catching a fish. Minutes later, Ash dozes off. When he wakes up, something pulls on his rod. Brock, May, and Max help Ash pull the thing out of the water. They finally are able to pull the thing out onto the deck. It is a Crawdaunt. May looks up Crawdaunt in her Pokédex. Since Crawdaunt is the evolved form of Corphish, Ash sends Corphish out. Both Corphish and Crawdaunt use Vicegrip. Crawdaunt's Vicegrip is more powerful, so it sends Corphish backwards. Crawdaunt then uses Crabhammer. Corphish also uses Crabhammer, but Crawdaunt's attack is more powerful, so it directly hits Corphish. Crawdaunt fires a Bubblebeam towards Corphish. Corphish tries to counter it with its Bubblebeam, but Crawdaunt's attack is too powerful for Corphish. Crawdaunt then takes the rods and breaks them.
Suddenly, a girl comes up to them. Crawdaunt jumps back into the water. Brock falls in love with her and asks for her name. The girl's name is Tiphany. She apologizes to Ash and co. for Crawdaunt attacking them. She tells a story about the fishing lake a year ago. It used to be really popular and a Dragonair lived in it. Then industries wanted to buy the lake and turn it into a spa. However, Timphany didn't want to do that. Then suddenly, Crawdaunt appeared and frightened everyone away. Ash wants to get rid of the Crawdaunt so that the lake can be saved.
Timphany's grandma walks up to them. She is a bit surprised that Ash wants to battle Crawdaunt. Everyone splits up to find Crawdaunt. Brock and Timphany go on a boat while Ash, May, and Max walk on the sides of the lake. Brock and Tiphany search around for Crawdaunt. Suddenly, Tiphany spots Crawdaunt heading into a cavern. Crawdaunt walks up to the industry guy that wanted to buy the lake. He gives the Crawdaunt food. The Crawdaunt is the industry guy's Pokémon. Ash and co. watch him. Team Rocket is working for the industry guy too.
Tiphany steps up to the industry guy. She wants him to leave right away. Ash wants to have a battle with him. The man agrees to the battle, however if he wins he gets the boathouse and lake. Tiphany accepts the battle. She says that they will have the battle tomorrow. He tells them a story about how he was pulled underwater and got tangled up in the fishing line. He eventually blacked out, but when he woke up he was on land. Then the man walks away.
Ash practices battling with Corphish and Pikachu. Then Tiphany's grandma states that Ash will never win that way. She sends out Vaporeon. May looks up Vaporeon in her Pokédex. She challenges Ash to a battle. Ash accepts her challenge.
The battle begins. Corphish starts off with Crabhammer but Vaporeon jumps into the lake and dodges the attack. Corphish goes after it, but Vaporeon disappears by using Acid Armor. Ash looks around but he doesn't see Vaporeon anywhere. Vaporeon suddenly strikes Corphish with Quick Attack. Corphish falls into the part of the lake where the seaweed is takes place. A Hydro Pump from Vaporeon knocks out Corphish. Tiphany's grandma tells Ash that he will never win with just power because Crawdaunt is stronger. Brock fills in that using the area and attacks skills as your advantage might cause you to win.
The next day the battle with Corphish and Crawdaunt begins. Corphish starts off with Crabhammer and Crawdaunt does the same, however both attacks are equal. Then Corphish fires a Bubblebeam, and so does Crawdaunt. Crawdaunt's Bubblebeam is stronger, so Corphish dodges and goes into the lake. Crawdaunt goes after Corphish with Vicegrip, but Corphish dodges the attack and hits Crawdaunt with a Crabhammer. Both Pokémon go on land again. Crawdaunt attacks Corphish with Vicegrip, but a Harden from Corphish stops the attack. Then with another Crabhammer, Corphish sends Crawdaunt back into a rock. The man orders Crawdaunt to get up.
Suddenly, a mechanical arm comes down and swipes Crawdaunt. Up in the sky is a green robot machine. Inside is Team Rocket and they say their motto. Then they snatch Pikachu and fly away. Everyone gets into a boat and chase Team Rocket down. The man wants them to help him rescue Crawdaunt. Marshtomp, Corphish, and Squirtle fire their attacks to Team Rocket. Team Rocket dodges the attacks. Squirtle gets an idea and tells Corphish about it. Corphish throws Squirtle into the air. Squirtle uses Rapid Spin to hit Team Rocket's machine. Then Squirtle falls down, but Marshtomp's Water Gun prevents it from falling. May tells Squirtle to use Rapid Spin again. Then Ash has Corphish use Bubblebeam to give Squirtle a boost. Squirtle charges right into Team Rocket. Team Rocket drops Pikachu and Crawdaunt. However, Team Rocket loses control of their vehicle, and they crash near Ash and co. Team Rocket blasts off again.
Everyone is washed up onto the shore except for the industry man. The man is sinking into the lake. Tiphany's grandma swims underwater to rescue him. Dragonair also comes to rescue him. The man now understands who rescued him before. It was Tiphany's grandma and Dragonair. The man is brought onto shore. He asks Tiphany's grandma why she didn't tell him that she saved him. Tiphany's grandma tells him that she didn't need to, but she did it because she loves the lake. Dragonair swims away. The man decides to quit his project and let Tiphany keep the lake.
The lake turns blue again, and all the Pokémon begin to come back. Max thinks that Dragonair told all the Pokémon that it was safe to come back. Everyone is happy that the lake has returned into its normal state.
