On a clear star-filled night, Ash and his friends watch the sky as Marian shows up, mentioning that there is a rare meteor shower. Everyone is awed by the show, when suddenly a meteor falls straight at the group. Piplup confidently jumps ahead and uses Whirlpool to stop the meteor and create a dazzling sparkle. When the light clears, they suddenly appear in a stadium filled with spectators, as that appeal gave Dawn the win for the Grand Festival. Everyone cheers for Dawn as she thanks Piplup. Suddenly, Gible appears and fires Draco Meteor, which comes down and hits Piplup. The attack appears to send Piplup flying, but the scene changes to show Piplup waking up in the middle of the night, the whole thing being a dream. Piplup goes back to sleep.
The next day, Ash decides to train, knowing that his final badge and the league is closing in. He decides to put time into improving Gible's faulty Draco Meteor. When he brings Gible out, it immediately sprints over to bite on a nearby boulder. Ash tries to pull Gible off, which results in his Pokémon biting on his head instead.
Gible starts practicing Draco Meteor, but every attempt continues to fail and hit Piplup, with Ash repeatedly apologizing to Dawn's starter Pokémon. After disrupting Piplup from smelling flowers, getting water from a stream and simply heaving the Penguin Pokémon everywhere, Piplup runs over to Gible and scolds it. When Gible responds by latching onto Piplup's head, the Water Pokémon unleashes his anger on Gible with Whirlpool and BubbleBeam attacks. Gible's lack of response only infuriates Piplup more as Ash and Dawn try to calm the chaos.
Piplup runs towards Dawn, imagining her and Ash scolding Gible and demanding it to apologize, Dawn caring only for Piplup. Instead, Piplup winds up hugging Pikachu. Pikachu comforts Piplup briefly before running over to Ash. Piplup notices that nobody is angry towards Gible, only supporting it and encouraging it to work harder to improve. This devastates Piplup, especially when Dawn says that Gible didn't do intentional harm. Crushed, Piplup walks away, nobody noticing him. Nearby, Team Rocket watches and decides to take advantage of it.
Piplup walks into the forest and takes a break. Hearing a nearby bush rustle, Piplup thinks its Dawn, fantasizing that she has taken Piplup's side. When he jumps into the bush, he runs into an angry Rhyperior, immediately facing a Flash Cannon attack, forcing him to run away. Piplup runs into the Team Rocket Trio (Jessie, James and Meowth), who are disguised as members as the Pokémon Rescue Group, a team that helps solve feuds between Trainers and Pokémon, as well as helping Pokémon that have been abandoned by their trainers.
Meanwhile, Ash and his friends search for Piplup, with the aid of Ash's Staraptor. Ash interrupts Gible gnawing on a tree and asks it to help search. Gible runs forward and latches onto a hidden Rhyperior's tail, aggravating it and forcing Ash and his friends to flee from its Flash Cannon.
Piplup, still with Team Rocket, tells about his problems with Ash's Gible and how he has reached his limit with the most recent event, even as going as far to say it's planning to head back to Professor Rowan's lab in Sandgem Town. Jessie comforts Piplup as she and James decide to find Ash and Dawn.
With no luck finding Piplup, Ash recalls Staraptor. Jessie and James, using their disguise, confront Ash and Dawn. After they tell Dawn how Piplup felt about the recent events, and getting the riot act read to them by the disguised duo, she and Ash realize that they owe Piplup an apology. While demanding that they take a counseling class, Jessie and James demand Ash and Dawn's other Pokémon. Before anything happens, the same Rhyperior shows up and fires a barrage of Flash Cannons, forcing them to flee, but it also separates Ash and his friends from Jessie and James. Pikachu also gets separated.
Jessie and James return to Meowth and Piplup, and begin putting another plan into motion by asking Piplup to find and bring Pikachu over, which he agrees to. Pikachu walks alone when Piplup finds him and brings him over. They enter a covered box which is revealed to be an electric-proof cage. Piplup is stunned at being fooled.
Ash and his friends are still trying to locate Pikachu and Piplup. Gible then fires a random Draco Meteor, which fails and falls where Team Rocket is located. Brock realizes that the move can be used in a good way as they head over, finding Team Rocket. Before they can finish their motto, the same Rhyperior shows up and unleashes another Flash Cannon, which frees Pikachu and Piplup. Dawn runs to Piplup, showing him that she did care as they both embrace, Ash also apologizing to Piplup. Team Rocket decides to battle, sending out Carnivine and Seviper. Ash sends out Grotle while Dawn lets Piplup jump into battle. Seviper launches a Haze, but Grotle's Energy Ball cuts through it and makes contact, taking down Seviper. Carnivine fires Bullet Seed, which Piplup matches with BubbleBeam, but a quick follow-up Vine Whip knocks Piplup down. Piplup gets up, bestowed with anger and strength, and launches his brand-new move, Hydro Pump, which sends Team Rocket flying sky-high.
The Rhyperior is still angry, as Ash and his friends try to calm the Pokémon, when a Trainer comes out and calls to Rhyperior. He reveals that he is Rhyperior's Trainer and apologizes to his Pokémon for being mean. They work things out and move along, which encourages friendship with Dawn and Piplup.