Summery: While walking through Celadon City, Ash co. learns that a number of children have gone missing. Brock offers to help Officer Jenny search for them, for all his usual reasons. They learn that the children have been missing for the past three days, and around the time that they disappeared, the Pokémon at the Poké Center started feeling sick. It seems logical that there's a correlation, but no one's sure as to what. Jenny thinks it may have something to do with the "sleep waves" (you are getting sleepy) that she's noticed recently. Following that hunch, the group tracks the sleep waves to a mansion, perched atop a skyscraper. The people in the mansion are insomniacs, and have recently taken in a Hypno, to help them fall asleep. Brock feels this is a bad idea, because Hypno's powers were never meant to affect humans. If Hypno has altered the wavelengths of its sleep waves, so that they will affect humans, then they might also have an adverse effect on other Pokémon. His suspicion is confirmed, when he learns that they got the Hypno three days ago. Misty allows the Hypno to put her into a trance, and she immediately begins to act like a Seel(Haha!), a type of Pokémon. She leads Ash, Brock, and Jenny to a park, where the missing children are hiding. They seem to think they're Pokémon as well. Brock reasons that this is another effect of Hypno's sleep waves. The Hypno's owner also has a Drowzee, and he thinks it can reverse the effects. The group returns to the mansion to retrieve it, but Team Rocket intervenes, attempting to steal Hypno and Drowzee. Ash beats them off, and rushes Drowzee to the park(GOoOoOoO Drowzee!!). Drowzee wakes the children from their trances, then heals the sick Pokémon at the Poké Center.  Psyduck Nurse Joy is worried, though, because one of the Pokémon still looks sick. The Pokémon, a Psyduck, appears to have a headache; and Brock offers to take care of it for her, to see if he can nurse it back to health. Then he passes it off to Misty. Misty is less than thrilled with this arrangement, and begins to protest. She accidentally drops one of her empty Pokéballs, and the curious Psyduck taps it with its beak. The Pokéball opens, and Psyduck is sucked inside. Misty is none too pleased... and then she learns that Psyduck always has headaches...(now I have one!!!)