Meowth wants to enjoy the last days of its vacation with a picnic lunch in the park. But Meowth's sandwich starts floating in the air, and it zooms away when Meowth tries to chase it! Meowth chases the sandwich through the park and runs right through the special reception Azumarill is preparing for Azurill, who is coming from out of down. After a commotion like that, all the Pokémon friends end up chasing the sandwich! When the sandwich goes flying, Teddiursa catches it and gobbles it down in one gulp. The other Pokémon spot a footprint that suggests it was an invisible Pokémon who first swiped the sandwich, but who?
Just then, Meowth sees a strange red stripe floating by. This must be the invisible Pokémon! One of the Pichu Bros. asks a Smeargle for help, and Smeargle throws paint around until the invisible Pokémon is covered in paint and plain to see. It's a Kecleon! Kecleon runs away, but its paint-covered footsteps lead the others to an empty pipe. Inside the pipe are Kecleon and the Azurill that Azumarill was waiting for: Kecleon was stealing the food for Azurill! Once everything is cleared up, the Pokémon settle down to a delicious picnic with friends.
The next day, the Pichu Bros. are helping Azumarill look after Azurill. But as soon as they take their eyes off the little Pokémon, it disappears! The Pichu Bros. gather all of their friends to help them find Azurill. Even though they can see it, they can hardly catch up as it bounces all over town! Not far away, Meowth is trying to win a pretty Skitty's heart with roses when Azurill bounces past, switching Meowth's roses for a bundle of laundry. Skitty is not impressed.
For Meowth's next attempt at romance, it tries to give Skitty a cake, but Azurill steals the cake and eats it. Then Meowth sings a romantic serenade, only to have Azurill ruin this chance at love, too! That's when the Pokémon pals show up and grab Azurill, while Meowth ends up stuck under a Snorlax. So much for love; Meowth decides to settle for a nice, peaceful nap instead!
Following five days of trying, Meowth has decided to give up on building a statue of himself and focus on enjoying the last two days of his holiday in Big Town. He opens his picnic basket, taking out a sub sandwich and drink canister. He looks over to a nearby Tauros statue and begins to daydream of people placing a giant golden Meowth statue up just for him. As he daydreams, he reaches to take a bite of his sandwich, but chows down on his hand instead. He screams from the pain, but then panics after spotting his sandwich hovering in mid-air. Meowth thinks he's just hallucinating and goes to grab the sandwich, but it slides away. He tries again, but his sandwich then takes off running. Meowth gets mad and chases it, now revealing that a red stripe seems to be carrying the sandwich.
Watching from a tree, the Pichu Brothers soon join the pursuit. Meanwhile, Azumarill is happily preparing a table for a lunch for its visiting friend Azurill. It places some flowers in a vase and steps back, knowing its table setting is now perfect. Smoochum, Magby, and Wooper watch on. Suddenly, the sandwich floats by followed by a very angry Meowth. Meowth leaps onto the table, destroying Azumarill’s hard work in the process. As Azumarill begins to fix things up, Meowth returns again, this time flipping the entire table over. Azumarill calls out to him and he apologizes, saying he wouldn't be in such a rush if his sandwich wasn't. The sandwich turns around and rushes towards the other Pokémon, then veers left. The other Pokémon decide to help and they chase after it, knocking Azumarill down. Now Azumarill is extremely mad, and it begins trying to Water Gun them. Meowth tells it to stop and ducks, but Azumarill is too mad.
Meanwhile, Teddiursa is also in the park. It digs at the ground and finds some acorn shells, much to its dismay they are empty. It then hears some commotion and turns to see many Pokémon chasing a floating sandwich. The stripe trips on a rock and the sandwich flies into Teddiursa's mouth. Meowth freaks out as Teddiursa chows down on his flying food. He tackles it and begins to knock it around, but Teddiursa has gulped the whole thing down.
The Pichu Brothers soon discover a footprint on the ground nearby. Meowth inspects it with a magnifying glass, and exclaims that when he figures out who the sandwich thief is, they will pay for his stolen sandwich. He sits on the ground and begins to think, but isn't having much luck. He begins to inspect the other Pokémon's feet, finding no matches.
Suddenly, the red zigzag waddles by. All the Pokémon begin to chase it through the park, knowing that it is the culprit. After some time, the stripe runs into a stadium. The Pokémon follow, but find the stadium is full of multi-colored zaigzag paintings. The group looks down to see a Smeargle happily painting the walls next to a bushel of apples. At first Meowth doesn't know what to do, but then it sees one of the apples float. Meowth tries to follow it, but it disappears. While Meowth tries to locate it, Pichu Big has Smeargle splash the paint on its tail everywhere, which reveals the invisible Pokémon is a Kecleon. Thinking it is still invisible, Kecleon tries to tip-toe away. Taking advantage of this, Meowth purposefully bumps into and steps over the Pokémon.
The Pokémon crowd around and Meowth tells it that he has caught it. Smeargle then shows its tail, and Kecleon that it is covered in paint. The Pokémon all give chase as Kecleon starts to scurry. But it disappears again. Meowth then notices a trail of yellow footprints, so they decide to follow them. After some time, the group comes to a concrete tube where the prints lead inside. They peer in to see the Kecleon taking care of Azurill. It opens its mouth and feeds it the apple. Meowth calms down after realizing that Kecleon only took the sandwich to feed Azurill, the same one visiting Azumarill.
As they meet up with Azumarill, who has finished redecorating the table, Kecleon adds that it found Azurill cold and hungry one stormy night. Azumarill thanks Kecleon and invites the whole group to have dinner with it at its table. Everyone sits down to a feast of fruits, happily enjoying the company.