Ash, Misty, and Tracey are riding on Lapras through the waters of the Orange Islands. Everyone is keeping busy; Ash is polishing the GS Ball, Tracey isPokémon watching, and Misty is playing with Togepi. All of a sudden, splashes of water in the distance become ever closer to the group. As the waves rush past, we see a kayak being propelled by a very tan Nurse Joy and her Chansey. Tracey recognizes the nurse, and Ash, unsure of what it was, orders Lapras to follow the boat and catch up to whatever had sped past.
They arrive at a small island, where they find a deserted kayak on the beach and two pairs of footprints in the sand. Tracey describes the prints as belonging to a Chansey and a woman with a size-7 sneaker. After following the footprints to a small bay, they realize there are no more tracks to follow. Misty states her uncertainty that what had passed them on a boat was a Nurse Joy. Tracey recalls the moment, saying that the woman seemed more muscular than an average Joy. Just then, a giant Magikarp jumped up out of the bay and began flopping around on the rock at the group's feet. Misty, worried that the Water Pokémon will run out of air, proposes that they help it get back into the water; Ash agrees. Before they can figure out how to help the Pokémon, Nurse Joy and Chansey appears to help Magikarp. Joy gives Magikarp a bottle of Calcium tablets and throws it back into the water. Nurse Joy tells Ash and his friends that she travels from island to island helping sick and injured Pokémon, because a lot of the Orange islands are too small forPokémon Centers. She invites the group to her local clinic for lunch.
Back at her clinic, Nurse Joy demonstrates her abilities by treating Ash's Lapras. Eager to see Nurse Joy in action, Ash and his friends ask if they can help with her work. Ash, Misty, Tracey, and Nurse Joy all set off in kayaks. We see the group in a variety of situations where Nurse Joy's assistance is needed. Many Trainers' Pokémon are helped: a Kingler, an Onix, and a Mankey, among others.
A little while later, the group falls behind in their kayaks, and loses sight of Nurse Joy. When they finally catch up to her kayak, it is empty; both Chansey and Joy are missing. Tracey believes that aGyarados could have tipped her boat over. Suddenly, they see a pink figure appear from the water, thinking it might be Chansey; the figure turns over and reveals itself to be Jigglypuff. Before the Pokémon can begin to sing, they race away in their kayaks. When they finally stop, they see Nurse Joy and Chansey, with its first-aid kit, pop up out of the water. She states that she went underwater to treat a sickCloyster, and sends Chansey to retrieve their kayak. Ash and Tracey become curious as to how Joy can treat Pokémon underwater, so she offers to show them. The boys in their swimming attire jump into the water and follow the nurse to the ocean floor. There, we see a sick Shellder that Nurse Joy begins to examine. Unable to hold his breathe any longer, Ash begins to struggle. Just then, a wild Dewgonggrabs onto him with its fins. The Pokémon seems to be playing with Ash. Nurse Joy rescues him from Dewgong and they all head back to shore.
At the clinic, Ash is warming up under a blanket with a hot beverage. The group collectively states that Nurse Joy's job is not easy, and that it would be easier to just run a Pokémon Center like all of the other Joys. She begins to tell a story from her childhood. She says when she was a little girl, she found a tiny injured Magikarp on the beach. She decided to take it home and nurse it back to health. When the Pokémon was healthy once again, she released it back into the ocean. A little while after that, while on a boat with her family, she fell into the water; she was then promptly saved by Magikarp, the same Magikarp that she had helped on its way to full health, who had grown considerably. Joy says that moment was when she decided to dedicate her life to Pokémon, especially those without Trainers to care for them. Misty asks her whether the Magikarp they had seen earlier that day was the same Magikarp she had helped. Nurse Joy says that it was, and that her and the Water Pokémon have been friends ever since that day.
Outside, the group sees the warning signs of an upcoming storm. Nurse Joy explains to them that she has one more stop for the day; Ash apologizes for throwing her off schedule. She says that when dealing with Pokémon, one should always expect the unexpected. Tracey expresses his worry over the surely upcoming hurricane, and states that it is too dangerous for Joy to go out on the water again. She says that there is a group of sick baby Seel waiting for her help. Despite Tracey's begging for her to wait until the storm passes, Nurse Joy leaves on her kayak with Chansey anyway. Worried for her safety, the group follows the nurse in kayaks without her knowing.
Out in the middle of the ocean, the choppy waves are making it difficult for everyone to control their boats. Ash shouts for Nurse Joy from behind, and she looks back in surprise. Just then, a huge wave sends Ash, Misty, and Tracey flying into the air and out of their kayaks. Nurse Joy yells to them to send out their Water Pokémon to help keep them afloat; Ash sends out Squirtle, Tracey sends out Marill, and Misty her Staryu (along with Psyduck, who is unable to swim). The nurse tells them to follow her to a nearby island.
On the very small island's beach, the sun is shining once again. With everyone safe from the ocean's wrath, Tracey apologizes to Nurse Joy for intervening in her efforts to help the baby Seel. Joy says that it was alright, and that they were just trying to help. Before continuing on their way to help the group of Seel, they decide to take a short rest. Suddenly, we see Team Rocket spying on the group from theirMagikarp Submarine. Intent on capturing Pikachu, as well as Chansey, Meowth seems very confident that they will succeed this time. He tells James that there is no way they can "lose" with his new secret weapon. Meowth then hits a button, which sends a torpedo-like object flying from the submarine, up and out of the water. The object releases a net that entraps Ash, Misty, Tracey, Nurse Joy, Pikachu, and Chansey on the beach. Appearing from the water in the mechanical Magikarp, Team Rocket recites their motto. Nurse Joy is intent on escaping, so she can help the baby Seel. Just as tears begin to form in her eyes, an ominous figure rams into Team Rocket's submarine from below the water. The giant Magikarp befriended by Nurse Joy jumps up out of the water with menacing glare. With numerous Tackleattacks, Magikarp tries to rid the ocean of the trio of thieves. As Joy calls out to the Pokémon for help, it begins to evolve. Using its newly formed tail, Gyarados whips Team Rocket off into the distance. Gyarados turns around to look at the group stuck in the net, and they begin to worry that its evolution caused a change in its demeanor. The Pokémon lunges towards shore, but, instead of attacking, Gyarados gets close to Nurse Joy so she can pet it. Gyarados removes the net with its mouth and flings it into the ocean. Misty exclaims that the Pokémon evolved into Gyarados, but kept Magikarp's personality. Joy thanks her friend for its help. Nurse Joy is finally able to reach the island that is home to the group of sick baby Seel, and treat them.
Ash, Misty, and Tracey admire the relationship between Nurse Joy and Gyarados. Tracey sketches the two of them together and says that if everyone would treat their Pokémon, and each other, with the care, love and respect they deserve, the world would be picture-perfect. Joy then remembers Ash telling her of his plans to become a Pokémon Master; she tells him of Navel Island. She says Navel Island is home to an Orange League Gym, and that he might be able to win a Badge there. The group head on their way atop Lapras.
- Giant Magikarp
- Giant Gyarados
- Tracey makes a reference to Florence Nightingale, a nurse who served in the Crimean War helping injured soldiers on the field.
- The Nurse Joy from this episode reappears in a photograph in a Pokémon Center run by her sister in EP250.
- Nurse Joy said she was treating a sick Cloyster, but when she is underwater, she is actually treating a Shellder.
- Despite being giant, the Gyarados that Nurse Joy's Magikarp evolved into did not appear to be any larger than a regular Gyarados.