The gang finds a Nurse Joy, who got stuck while looking for and getting a mega stone. They ride to the Pokémon Center where they meet Professor Sycamore, and an Audino, who serves as an assistant, but the two don't seem to get along. But when Team Rocket appears with a weapon that might just help steal all the Poké Balls, they have to bond together to stop them with the help of the Mega Stones.
As the heroes travel, they try to find the Pokémon Center, where the professor is waiting for them. Suddenly, they hear a scream, so they run off to investigate. They find a woman, who got her leg stuck in a fissure. The heroes leap down and attempt to pull the woman out, but fail. Bonnie asks her brother for help. Clemont's eyeglasses shine, as he prepares to show a new machine, but is interrupted by Bonnie, for he has to do something immediately. Clemont uses the Aipom Arm to push the rock, allowing Bonnie, Serena and Ash to pull the woman out of the fissure successfully. The woman admits she got stuck when searching for a Mega Stone, which she retrieved successfully. Seeing the Mega Stone, Bonnie reminds everyone the Professor Augustine Sycamore is waiting. As a token of gratitude, the woman decides to lead the heroes to the Pokémon Center.
The woman shows the ambulance wagon and removes her clothes, revealing to be Nurse Joy. Joy admits that is what she looks like when she is out on the field, since the heroes are surprised. When Nurse Joy takes the heroes to the Pokémon Center, a boy sees the wagon and runs off. Team Rocket notices the twerps exiting and see the "stupid" Nurse Joy, who leaves her Pokémon Center unattended. Seeing even the twerps are here, they know it is their chance of catching Pikachu. The heroes enter the Center, glad to see they came before the professor. Nurse Joy goes to heal their Pokémon, but cannot open a door. Clemont inspects and finds someone blocked the door behind. Nurse Joy orders Audino to open up. The heroes are surprised, but Clemont remembers some regions have Audino as assistants.
Audino refuses to open. Nurse Joy sees Audino is now upset, as Nurse Joy had left without letting it know when it would come back. The heroes leave the Center to have Nurse Joy have a talk with Audino. Ash wishes they could influence Audino to forgive Nurse Joy. A boy comes to them, introducing as Emilio, who also wishes to see Audino and Nurse Joy behaving on good terms. Emilio shows them a way in, through the window, to find Audino. They enter the Pokémon Center and find Audino taking care of a Zigzagoon, ignoring Nurse Joy's words. The heroes ask Audino if it can forgive Nurse Joy, else the Pokémon Center may be in trouble. Suddenly, Prof. Sycamore exits his car and sees a man carrying his Makuhita to the Center. They both enter the Center and Sycamore sees the situation is bad. Nurse Joy manages to get Audino to open the door and immediately asks to prepare the equipment to treat Makuhita. The heroes encounter Sycamore, who needs their help.
Inside the operating room, Nurse Joy counts on Audino for assistance. While Nurse Joy and Audino are healing Makuhita, Sycamore exits the room, claiming Makuhita will be in good shape soon. Sycamore notices the Mega Stone, which Joy found earlier. Nurse Joy and Audino are finished, as Makuhita leaps into the man's grasp and hugs him. The man thanks Nurse Joy and Audino, then leaves. While Nurse Joy and Audino go to clean up, Sycamore commends Audino and Joy both make a good team. Bonnie wonders why are they fighting all the time. Clemont reminds Sycamore of Squishy. Bonnie shows Sycamore Squishy, who examines it a bit. Sycamore lets the heroes know he sent some forms to other research stations, seeing what they think of it. At any rate, Sycamore takes a slight sample, wanting to examine Squishy's cell structure later.
Sycamore opens the door and everyone sees Nurse Joy arguing with Audino. The heroes ask why do they fight all the time, so Nurse Joy lets them know when she was promoted and assigned to a Pokémon Center, she got an Audino instead of a Wigglytuff. Nurse Joy asked why an Audino, so her superior told her she tends to forget certain things at a time, so Audino can cover in for her. Nurse Joy thinks she tries to think of certain things, but Audino meddles in her business. Sycamore shows Nurse Joy the Mega Stone she obtained. Joy replies she wanted to find ways to understand Audino better and shows her the book about Mega Evolution. Audino can Mega Evolve, giving Nurse Joy the idea of using that to heal their patients even more and better. She wanted to surprise Audino with the Mega Stone. Sycamore admits he has a device that can scan the Mega Stone.
Outside, Team Rocket watches. Jessie and Meowth see the Poké Balls they can take, while James overhears the conversation about the Mega Stone. Sycamore places the Mega Stone with the Key Stone, confirming it is a Audinite. Sycamore is certain the Mega Stone will be useful for Audino, who is glad Nurse Joy found it. Suddenly, a crash sound is heard and everyone comes out, seeing Team Rocket has attacked the building. They confront Team Rocket, who is taking the Poké Balls away, in what they call "Giga Mega Evolution mecha", the Giga Giga Meowth Machine. Meowth has the machine entangle Ash and Pikachu in a net and pulls them. Nurse Joy and Audino demand they leave, since they came here to protect the Pokémon Center. Meowth goes to suck up the Mega Stone into the machine, but Sycamore throws Joy the Key Stone, who activates it, Mega Evolving Audino.
Mega Audino crushes the arm of the machine. Team Rocket sees it is starting to feel bad and may have to retreat. Mega Audino uses Power-Up Punch, freeing Ash and Pikachu. Mega Audino attacks the machine with Double Slap, Take Down and Power-Up Punch. Mega Audino uses Heal Pulse, which softens Team Rocket, making them fuzzy, causing them to release all Poké Balls. After that move, Pikachu uses Thunderbolt, blasting the fuzzy Team Rocket off. Later, Nurse Joy, after giving the Key Stone back, thanks the heroes and Sycamore for helping them in making up with Audino, admitting they won't fight each other from now on. Sycamore, however, plans on doing research on Squishy and bids the heroes farewell, who continue towards Snowbelle City.
Later, as Audino heals a Zigzagoon with Heal Pulse, Nurse Joy yells her to open up, apologizing for eating all the candy.
- Audino to Mega Audino
- Hoothoot (Trainer's)
- Pansage (Trainer's)
- Ducklett (Trainer's)
- Bibarel (Trainer's)
- Psyduck (Trainer's)
- Pachirisu (Trainer's)
- Smeargle (Trainer's)
- Teddiursa (Trainer's)
- Makuhita (Trainer's)