A Chip Off the Old Brock (Japanese: ミズゴロウとモココ！恋の特効薬！？ Mudkip and Flaaffy! The Wonder Drug of Love!?) is the 3rd episode of Pokémon: Battle Frontier.
From the sunlight, Mudkip comes down onto the ground, Grovyle jumps out of the way. Ash and Brock are having a battle. Ash tells Grovyle to use Bullet Seed, Mudkip dodges the attack. Grovyle then strikes Mudkip with Leaf Blade. Suddenly, a bright light glows on Mudkip - It evolves into Marshtomp. Impressed, May looks up Marshtomp in her Pokédex. Marshtomp fires a Mud Shot at Grovyle, but Grovyle dodges the attack. The attack heads for Ash who dodges it. It goes through the bushes hitting a Flaaffy. A young girl arrives and cares for Flaaffy. Ash apologizes to the girl for the damage that they have done. Since Mud Shot is a ground type attack, it is super effective against electric types like Flaaffy. Brock offers to get some medicine for Flaaffy, but the girl declines Brock's offer. The girl runs into a drug store. Then Ash and co. follow her to the store.
An old woman holds out a potion and gives it to Flaaffy. Flaaffy is stunned for a bit, but quickly heals. Ash and co. are happy that Flaaffy is better. The girl thanks her grandma for the potion, then she gives Flaaffy a hug. Brock and Ash apologize again. The old woman hears that Ash is training for the Battle Frontier. Ash and co. introduce themselves. The girl introduces herself as Miraya and her grandma, Katie. Brock immediately falls in love with Miraya. Marshtomp, who has hearts in its eyes, holds Flaaffy's hand. Marshtomp has a crush on Flaaffy. Before Brock can go crazy, May and Max pull Brock and Marshtomp away. Ash is impressed at the medicine that healed Flaaffy. Miraya explains to Ash that her grandma makes the best medicine for Pokémon.
A boy comes in with an orange - looking potion. He gives it to Katie for a test. Katie tastes the medicine. She tells him that she can't sell it since he did something wrong. The boy feels down since he messed up. Miraya tells him she is sure that he will do better the next time. The boy sees Ash and co. Miraya introduces Ash and co. to Micolie. They both work at the medicine shop.
Team Rocket is admiring the medicine shop from a distance. They plan to steal all the medicine. Katie decides to make some more medicine with Miraya. Brock wants to watch her because it would make him a better breeder. May and Max decide to watch too. On the other hand, Ash decides to train some more for his challenge at the Battle Arena. At another house, Katie begins to make another potion. Brock takes notes as she mixes a few ingredients up. As soon as she finishes it, electricity is needed. She sends out her Mareep. Mareep uses Thunder to complete the potion. As soon as the time is right, Katie tells Mareep to stop the electricity. A perfect potion is made. Brock is beginning to understand the process. Miraya adds in that her grandma invented the process, but the hard part is deciding how strong the electricity should be.
Two customer walks in the medicine shop. Micolie, who is watching over the shop, greets the customers. The customers present a sick Snorlax to Micolie. They want some medicine to heal it. The customers are really Team Rocket in disguise, and Meowth and Wobbuffet are in a Snorlax costume. Jessie and James begin to take the medicine from the shelves, and they stuff it into the Snorlax costume. Then they run off. Micolie chases them down. Ash sees Team Rocket getting away. He has Grovyle use Bullet Seed to stop them from escaping. Team Rocket is revealed. Micolie grabs onto the costume wanting it back. Jessie refuses to give it back. Brock has Marshtomp use Mud Shot at Team Rocket. Team Rocket slips backwards and they land on a boat in water. The boat sails backwards down a waterfall. Micolie returns the medicine back to Miraya. Miraya asks if Micolie is okay, she is glad when she hears that he is fine.
At night, Brock grooms Marshtomp while talking about how he and Miraya would make a perfect couple. Ash shines his Poké Balls and tells Pikachu that they will be at the Battle Arena soon. Then he looks out the window and sees a blast of electricity come from inside the house outside. Ash and co. walk up to the house and look inside. They see Micolie and his Pokémon, Ampharos. Ampharos is using its Thunder attack to complete Micolie's potion. Ampharos overdoses the power and the potion explodes. Ash screams as some of the potion falls down near him. Micolie hears his voice. May thinks that it has gotten late for Micolie to practice his medicine making, but Micolie is determined to make a perfect potion. Micolie explains to Ash and co. that he has known Miraya ever since he was little, and he loved to watch Katie make potions. He has been inspired from Katie to make wonderful potions, but he always fails. Katie walks in and tells Micolie that he lacks confidence. All he needs to do is make that change and everything will be fine.
Suddenly, the ground begins to shake. Everyone rushes outside, and they see the medicine shop flying. Miraya is still inside the medicine shop. The shop is being pulled up by Team Rocket and their balloon, They say their motto. Max notices that Team Rocket has Mime Jr. Micolie walks on a rooftop and shouts out to Miraya that he will save her. Him and Ampharos jump from the rooftop and on to the medicine shop that is in the sky. Meowth gets out a remote control. He presses a few switches that shakes the shop. Miraya holds onto Micolie trying to pull him on board. The medicine from the shelves fall and break. Meowth makes their rockets even more powerful. Ash and co. try to chase after Team Rocket. Katie tells Brock to have Marshtomp use Mud Shot. Marshtomp fires the attack at Team Rocket, but Meowth has the attack reflected back at Ash and co. The attack damages Pikachu and Mareep. Katie calls out at Miraya and Micolie for some medicine for her electric Pokémon. Miraya and Micolie tell Katie that all the medicine fell down and was smashed. Mime Jr jumps on the remote and begins to press all the buttons at once. The balloon shakes around, and the rockets die out.
Micolie picks up two remaining potions that survived. He decides to combine them together in order to help the injured electric Pokémon. While James and Meowth are fixing the rockets, Ampharos is using its Thunder attack on the potion. Miraya hopes Micolie's plan works. Micolie has Ampharos use Thunder at its full strength. Miraya has Flaaffy help power up the medicine. When bubbles begin to form, the two electric Pokémon stop their attacks. When the rockets are fixed, Team Rocket begins to float away again. Micolie throws the potion to Katie. Katie examines the potion and is happy that Micolie finally made something good. When the potion is given to Pikachu and Mareep, they fire their Thunder attacks at Team Rocket. However, Team Rocket reflects the attacks back at them. Then Flaaffy and Ampharos use their Thunder attacks at Team Rocket. The rockets die out again causing Team Rocket to fall. Miraya and Micolie rush out of the medicine shop. Ash and co. surrounds Team Rocket. Team Rocket wants to battle. Jessie sends out Seviper and James sends out Cacnea. Seviper uses Poison Tail and Cacnea uses Needle Arm. Marshtomp shoots out a stream of water weakening Team Rocket's Pokémon. Finally, Flaaffy and Ampharos use their Thunder attacks on Team Rocket. Pikachu and Mareep also fire their Thunder attacks at Team Rocket. The combined force causes Team Rocket to blast off.
Katie is impressed that Micolie managed to create a potion. Micolie tells her that Miraya, Ampharos, and Flaaffy all helped him. Miraya adds that it was also Micolie's confidence that helped him make the potion. Katie decides to give the shop to Miraya and Micolie. Brock and Marshtomp sigh. It's time for Ash and his friends to head on the road again. Katie tells Ash how to get to the Battle Arena. May is carrying a bag full of medicine for Pokémon. They all say goodbye to each other, and Ash and co. head down to the Battle Arena.
Max told that Mud Shot is Earth type, while it should be Ground type.