On the way to Solaceon Town, Ash and his friends hear that the local "Scarf Monster" has made the tabloid news. Ash is skeptical, even though he and his friends see a shadow in the forest that looks much like the rumored monster itself. But once he arrives at his friend Angie's house, which is also a Pokémon Day Care, Angie acts strangely whenever the Scarf Monster is mentioned. When she runs out of the house, Ash and his friends follow her to a cave and discover that the Scarf Monster is a Lickilicky from her Day Care!
Lickilicky was a Lickitung at the Day Care which accidentally evolved after Angie taught it Rollout—and evolving another Trainer's Pokémon is a big no-no! Angie's parents are away on a trip, so she's hidden Lickilicky in the meantime. But Lickilicky also hates being a Poké Ball, so it always wanders off in search of food. As for the scarf, it's an inflatable collar that Angie uses to float Lickilicky in the air so she can haul it back home like a balloon. When she inflates the collar, Lickilicky's floating shadow attracts Team Rocket, who are posing as tabloid reporters and searching for the Scarf Monster. Fortunately, Dawn and Brock manage to hide Lickilicky from Team Rocket's prying eyes.
The next day, Team Rocket tests out a new robot designed to lure the Scarf Monster out of hiding. The robot has a giant ball of Pokémon food, and sure enough, Lickilicky comes right over to the source of the delicious smell. However, Team Rocket doesn't realize their valuable monster is a regular Lickilicky until Ash and Angie come looking for the missing Pokémon. Angie has Lickilicky wrap up Team Rocket so Pikachu can send them into orbit, and our heroes are delighted—until Angie's parents return from their trip. Fortunately for Angie, the Lickitung's Trainer is thrilled to have a new Lickilicky! Now she can say goodbye to Ash with a light heart as her friend heads for his next stop, Hearthome City!
Arriving back in Solaceon Town, Ash and his friends are in a park reading an article in the Sinnoh Star about a mysterious scarf monster roaming the town, causing widespread rumors, but they don't seem to be interested. Having decided to visit Angie while they are passing through, the group head on their way but soon spot a shadow of a mysterious creature that looks similar to the monster the article was referring to, though the shadow soon disappears.
Upon arriving at Angie's house, the gang greets themselves once again to an old friend. After having dinner, Ash tells Angie of a mysterious creature they saw. Angie becomes worried and leaves the room immediately. The gang follows her to a cave where she says to keep the mysterious creature, but the problem is the creature is nowhere to be found. Team Rocket, who are trying to track down this creature, are acting as news reporters. They spot Officer Jenny standing in front a pool of water and Team Rocket asks the police officer of any evidence of what the clue is. Officer Jenny replies that it is saliva. Back at the park a trap is set to catch the creature, the trap succeeds as the creature comes closer and closer to the trap. The creature turns out to be a Pokémon, a Lickilicky. Angie tells the gang that she was looking after a Lickitung when suddenly it used Rollout and evolved and, according to daycare rules, the carer must not let a Pokémon evolve at any circumstances.
Team Rocket asks Ash and his friends where the creature went, which Ash lies about. As Team Rocket leaves, Angie inflates the tube surrounding Lickilicky's neck with helium, which makes it float, and they return it to the cave. Nearby, a man fishing spots a creature in the forests flying overhead and is terrified.
The next day, Team Rocket creates a mecha to catch the creature. This machine lures the creature by using a ball of Pokémon food, which the smell will lure the creature to it. The plan succeeds as the Lickilicky follows the scent. Ash and Angie go to the cave to get Lickilicky, but then they see nothing but a broken rope. As Lickilicky is approaching the ball of Pokémon food, Ash and friends arrive to tell Team Rocket that it is actually a Lickilicky, but they disagree as a Lickilicky doesn't wear a tube. Angie gets furious and orders Shinx to use Crunch on the tube to pop it. Team Rocket realizes that it really is a Lickilicky, but Jessie refutes this, claiming the tube makes it the creature. They try to capture Lickilicky, but the tables turn and Team Rocket are blasted off by Pikachu's Thunderbolt. At that very moment, Angie's parents arrive.
After telling them what happened, Angie's father is furious, but as the Trainer of the Lickilicky is actually happy about the evolution, Angie is let off easy as the gang says goodbye to Angie. As Angie waves to them, her parents jokingly tell her that if she and Ash got married, they could look after the daycare. Angie frantically tells them not to say things like that, while Ash suddenly sneezes.