Pikachu is climbing in a tree when something gets stuck in his throat. Brock quickly suggests that they take Pikachu to see a doctor. They search for a Pokémon Center, but there isn't one for miles. They eventually reach a hospital for humans and ask for help from a doctor. The doctor, Dr. Proctor, doesn't pay much attention to Ash's pleas, but when Misty starts pleading, the doctor gives in, saying that he can't resist a pretty face. Thinking Misty is the one in need of help, the doctor asks her what the problem was. After explaining that Pikachu was the sick one, Ash once again asks for help. Although a hospital for humans, the doctor agrees to help; however, the doctor refuses at first. After checking on Pikachu, the doctor states that there is something stuck in his throat. The doctor manages to remove the thing in his throat, which happens to be an apple.
The phone then starts ringing; when the doctor refuses to answer, saying he is off duty, Brock answers for him and learns it is Nurse Joy. She informs the group that there has been a violent accident involving a truck of Pokémon stolen by Team Rocket, and the Pokémon are in dire need of medical attention. With the Pokémon Center at full capacity, the extra room in the hospital is needed. Instead of giving Nurse Joy a serious answer, he asks her out, making her angry. Meanwhile, Team Rocket are at the scene of the accident, with Jessie blaming James for the accident. Meowth is feeling down because the charm on his head is missing. Back at the hospital, the doctor gives doctor coats to Ash and Brock and a Nurse Joy outfit to Misty, as well as equipment, saying that he needs their help due to a staff shortage. When the injured Pokémon arrive on stretchers pushed by Chansey, everyone starts working. Ash calls out his Bulbasaur to hold down Cubone who keeps on struggling in pain. Misty comforts it and successfully calms it down. Dr. Proctor says that Misty is a natural.
Team Rocket comes in, bringing more patients, namely Jessie's Arbok and a Raticate. The doctor proceeds by asking Jessie on a date. Jessie is impressed with the doctor. Ash tells the doctor not to help Team Rocket, but Dr. Proctor explains that it was his job to heal, not to judge. Meowth is still stressing over the loss of his charm; Chansey tries to cheer him up, but does not succeed.
Everyone, including Jessie and James, work collaboratively to help all the injured Pokémon. A Pinsir, a Weepinbell, a Voltorb, a Hitmonlee, a Nidoking, a Sandslash, a Parasect, and James's Weezing receive medical attention. There is a Dodrio in need of untangling, so the doctor prepares an anesthetic injection, so as to calm it down. The Dodrio lunges at Dr. Proctor, causing the doctor to inadvertently stab himself with the anesthetic needle and falls asleep. With no doctor on hand, Ash decides to weaken Dodrio with his own Pokémon. He has Squirtle use Water Gun followed by Pikachu's Thunderbolt. Caught up in the moment, Ash pulls out a Poké Ball to catch the Pokémon, though Brock intervenes, telling Ash they are there to help the Pokémon.
Later, while treatment is still going on, Jessie and James decide that they are going to steal all of the injured Pokémon. They take off the uniforms and start reciting their motto. However, Meowth unexpectedly interrupts them, still wanting his charm. Jessie and James try to hold back Ash, Misty and Brock with a "stretcher catcher" contraption. Chansey faces James, who threatens Ash with a big needle. Jessie commands Arbok and James commands Weezing to attack Chansey, but they don't budge one bit. Dr. Proctor, who has just awoken, states that Arbok and Weezing will not attack Chansey because they were cared for by it when they were injured. Getting angry, Jessie throws a beaker at him, but Dr. Proctor simply cuts it in half using a scalpel. Dr. Proctor then shows them his arsenal of sharp tools, such as shots, scissors, and scalpels. Ash and his friends are freed by the Chansey. Team Rocket runs out of the building being chased by the "stretcher catchers" Ash and his friends had pushed their way. Team Rocket ends up blasting off again when the Voltorb that James sneaked away with self-destructs. Upon landing, Meowth becomes ecstatic when his charm pops out of his head, where it had been all along.
With all the Pokémon treated, Dr. Proctor suggests that Ash and his friends should become doctors and offers them some training. Misty states her interest in becoming a doctor, but adds that she still has a lot to learn about Water-type Pokémon. Ash and his friends then bid farewell to Dr. Proctor and continue on their journey.