Dawn's Piplup is at a waterfall. He begins to glow, but suppresses the power and feels exhausted. Next day, Dawn is ready to train for her Contest and sends all her Pokémon. Piplup is ready, but acts strange. Suddenly, Barry gets his hand banged into Ash's and sees they are here. Kenny also arrives and greets Dawn as Dee-Dee. Though Dawn does not want him to call her like that, Barry asks if they know each other. Barry tells that although they met each other recently, they both originate from Twinleaf Town and became friends. Since Kenny is entering the Contest, Barry announces he will enter the Ping-Pong Tournament. Ash does not know about this, so Barry explains as soon as the Contest is over, the Ping-Pong Tournament will be held where the trainers and Pokémon will work together to win.
Barry sends Empoleon to train for the tournament. As he is doing this, Piplup glows again and evolves, but suppresses the energy. This causes him to be exhausted and falls down. They all go to the Pokémon Center to treat him. Nurse Joy tells Piplup will be okay, he needs rest. While having dinner, Dawn comments that she still thinks it is a surprise it evolves, though she expected this day. Kenny and Barry know this is a token that the trainer is good in his/her job, while Ash reimds her that she will need to change her tactics as he did with Grotle. Dawn reminds him she had to do it with Mamoswine, while Brock is thinking of something. Team Rocket overhear and plot to get the set of Piplup, Prinpulp and Empoleon for the boss.
When Piplup wakes up, he sees himself in the window and sees a Prinplup of himself. Dawn enters and offers Piplup food, but he does not want to. Dawn imagines what will it be when Piplup evolves, but Piplup does not want to and upsets himself. Dawn calms him down and he begins to glow, meaning he is evolving. Piplup uses Bide to suppress the energy, so Dawn asks him why is he doing this. Dawn tells him he will be able to learn new moves and win Contests more effectively. Piplup is very angry and escapes the building, so Dawn goes after him. Barry pushes Kenny, Ash and Brock to train for the Tournament. Brock tells him he never said that he was going to enter the Tournament, but Barry responds they will be the strongest Ping-Pong team the world would know. Dawn comes and tells them what happened.
Brock now realizes that Piplup does not want to evolve and uses Bide to get the energy off. So, everyone goes to search for Piplup. Kenny sends Prinplup and goes with Barry. Dawn goes in other direction and sees some light from the woods and goes there. She sees Piplup uses Bide once more to stop from evolving. Dawn would like to know why is he doing this, thinking Piplup wants to evolve. Hearing this, Piplup is angry and uses BubbleBeam on her, then goes in the woods. She sees Piplup is engulfed in a web and spots an Ariados. Piplup uses BubbleBeam and hits it, though Ariados uses Mud Shot, but misses Dawn. The Mud Shot hits the web and Piplup goes in air, but Dawn gets him. Suddenly, the Ariados gather and use Hyper Beam, so Piplup uses Bide to protect himself and Dawn, then releases the energy to send the Ariados away. Piplup is exhausted, so Dawn gets him.
Kenny and Empoleon have not found Piplup and go somewhere else, but Prinplup and Empoleon get caught by robot arms. Prinplup uses BubbleBeam and Empoleon Hydro Cannon, but get spinned so much they faint. A strange machine awakens and Barry and Kenny are somewhat intimidated by the presence. Dawn and Piplup came to a river and Dawn thanks Piplup for saving her life and recalls the same thing happened when they met each other. Ash and Brock come and see Piplup is okay and go to the Center, but Piplup gets abducted. Team Rocket stole them all, so Pikachu uses Thunderbolt, but they invented a new device which absorbs electricity and hits Empoleon and Prinplup instead. Team Rocket drives, so Dawn goes on the machine.
She goes to Piplup and promises him to get him out. Though effortless, she goes into the machine and demands Piplup back from Team Rocket. Suddenly, Piplup comes from the air shaft and Meowth translates if they are to hurt the twerp, they need to pass though Piplup first. Dawn tells him she will protect him, but Piplup swore to protect her. Dawn realizes that the Bide he used was to not evolve. Meowth is touched by this story, as he also swore to protect the boss from getting the Persian. So, Dawn orders Piplup to use Whirlpool, which causes the robot to crash. Empoleon and Prinplup are free. James sends Carnivine and Jessie her Seviper, who use Bullet Seed and Poison Tail. However, Piplup's BubbleBeam negates the attacks. Piplup is about to evolve, so James tells him not to evolve, but Jessie thinks if the boss would get three Empoleon, he would be even more pleased.
Seviper and Carnivine attack, but get shocked, as Ash, Brock, Kenny and Barry arrive. Seviper uses Poison Tail and Carnivine Bullet Seed, but get hit by Thunderbolt. With Piplup's Whirlpool, Team Rocket blasts off. Dawn apologizes that she could not understand Piplup did not want to evolve, but promises to be a team, even as a Piplup. Next day, Nurse Joy treated Empoleon, Prinplup and Piplup. Nurse Joy also gives Dawn an Everstone, which should prevent Piplup from evolving. Dawn thanks Nurse Joy and thanks Ash for wishing her good luck on the Contest.
- There is no Professor Oak's lecture following this episode.
- Darkrai and Giratina replace Dialga and Palkia respectively in their appearance before and after the preview of the next episode.
- Music from Pikachu and Pichu, Celebi: Voice of the Forest, and Pokémon Heroes is used during this episode.
- In this episode, Dawn and Piplup underwent the same experience against a group of wild Ariados as when they first met; the same encounter that helped Piplup trust Dawn.
- This episode is similar to Bulbasaur's Mysterious Garden, where Ash's Bulbasaur was in the process of evolving and ultimately decided not to.
- When the dub's title was revealed, it was originally thought to air with Old Rivals, New Tricks! on September 5, 2009 but was pulled back to August 29, 2009.
- The dub title is a reference to Stop! In the Name of Love, a song recorded by The Supremes.
- In the dub, when Dawn was talking to Ash she said "Plinplup" instead of "Prinplup".
- After Piplup uses Whirlpool and destroys the mecha, when Piplup checks on Prinplup, its wings are the same color as its head and "cape" for a split second.
- While Team Rocket is blasting off, the background keeps repeating clouds, despite the fact that they are going up, and not sideways.
- Also, the background repeats the same frame the whole time.
- In the dub, Piplup opted not to evolve in order to preserve the memories of the day he met Dawn. In the original, Piplup didn't want to evolve because he was afraid of ending up like Mamoswine.
- In the European Portuguese dub, Kenny reads the title card.