Ash,Misty, and Brock have arrived in HopHopHop Town. As they walking through the streets, a woman runs up to them yelling, "Arnold!" and gives Ash a big hug. Ash says to the woman that his name is Ash, not Arnold. The woman apologizes and says Ash looks like her son Arnold, who is one of the missing children. The woman explains that sevral children have gone missing and no one knows why. The woman shows them a wall with pictures of the missing children on it as Officer Jenny puts up a new picture. Brock voluntiers to find the missing children. Ash remembers his own mother and he volunteers as well.
All of the missing children have been missing for three days. Ash and his friends go to the Pokemon Center and they start asking about them. Nurse Joy tells them that all of the Pokémon in the center have been losing their energy since three days ago. Officer Jenny's phone starts picking up some sleepwaves as Pikachu starts falling asleep. Ash and his friends head off to find the source of the sleepwaves.
Team Rocket is also looking for the source of the sleepwaves. They are plotting to use it to put their boss to sleep so they can take a vacation. They start crying about how long it has been since they have had a vacation.
Ash and his friends track the sleepwaves to the top of a skyscraper. They go to the top of it on an elevator. They reach the top and find a mansion on top of the skyscraper. They run inside the mansion and find a group of adults and a podium, which a Drowzee and a Hypno are sitting on. The adults explain that their old Drowzee evolved into a Hypno and they are using its sleepwaves to fall asleep easier.
A man explains that they are the Pokémon Lovers' Club and that they love Hypno the most. City life is hard on them and they were working hard to get their Drowzee to evolve so they could use its sleepwaves to sleep better.
However, Brock explains that Hypno's sleepwaves are used mostly on Pokémon and when it tries to use them on people, it causes Pokémon to lose their energy and the waves affect super sensitive kids. Misty is curious about the last part and she lets herself be hypntized by Hypno. Hypno uses Hypnosis and Misty starts acting like a Seel. She then runs out of the mansion and into a park where all of the other hypnotized kids are, who are also acting like Pokémon.
Brock explains that Hypno's waves are making the kids think they are Pokémon. Officer Jenny tries to wake them up, but it doesn't work. The head of the club suggests that they try using Drowzee's sleepwaves to counter Hypno's sleepwaves.
Back in the mansion, Drowzee's waves wake Misty up. Ash carries Drowzee into the park and Team Rocket appears. Jessie pulls out a mirror and tries to get Hypno to hypnotize itself. Ash throws a potted plant and breaks the mirror. Jessie then drops a net, picking up Drowzee and Hypno. James and Meowth ask Jessie why they didn't do this in the first place and Jessie replies," We have to fill the half hour." Staryu cuts the net and Pidgeotto blows Team Rocket away.
Drowzee wakes up the children as the children's parents come in with Officer Jenny. The woman from the beginning of the episode comes up and thanks Ash for finding her son. They take Drowzee to the Pokémon Center and they cure the Pokémon their also.
Nurse Joy notices a Psyduck is still holding its head. Brock volunteers to take it, but then outside of the center, gives it to Misty because she is a water type Pokémon trainer. Misty drops one of her Poké Balls and Psyduck walks up to it and lets itself be captured.
- The rings in Nurse Joy's hair are colored in when they should have been clear.
- Ash remembers his mother and Professor Oak saying goodbye to him and his friends. However, this happened in IL018: Beauty and the Beach, an episode which was banned. In the original version, Ash's flashback was from IL001: Pokémon - I Choose You!.
- Ash recalls meeting the Nurse Joy at Maiden's Peak in this episode.
- The line "We have to fill the half hour" is one of many cases of breaking the fourth wall in the series.
- Misty also breaks the fourth wall when she responds to the narrator's congratulations at catching Psyduck: "Don't congradulate me!"
- One of the children hypnotized by Hypno wore an outfit similar to that of Tracey Sketchit.
- The book Psyduck Ducks Out is based on this episode.
- At the end of the episode, It shows Psyduck in a purpleish circle. This may be the inside of a pokeball.
- The "Who's that Pokémon?" in this episode is Psyduck.
- Ash: "Are you the cousin or second cousin of the Jenny at Maiden's Peak?"
Officer Jenny: "Well actually, I'm her cousin's cousin."
Ash: "It figures."
- Ash: "I bet you're related to the Joy at Maiden's Peak."
Nurse Joy: "You'd win that bet."
- Misty: "What happened?"
Ash: "Gee Misty, you look kinda beat."
Misty: "When I want your opinion I'll ask for it!"
Ash: "She's back to normal."
- James: "Why couldn't we do this before?"
Jessie: "We have to fill a half-hour."
- "Don't Congratulate me!"
Misty yelling at the narrator.
Watch this and other episodes: Pokémon Episode 27: Hypno's Naptime