Team Rocket is in their secret base, about to eat. Jessie goes to get a snack but soon realizes there is only one cream puff left in the fridge, which James says is his. Before Jessie can take a bite, Mareanie uses a new move on Jessie. The cream puff lands on the floor next to Mimikyu, and it is quickly eaten to everyone's horror. Meowth then points out that Mareanie used a Dark-type move, Knock Off, delighting Jessie and James. Jessie notes that now that Mareanie knows a Dark-type move, they have an attack compatible with their Darkinium Z, but they need a Z-Ring to perform the move.
The trio is suddenly contacted by Giovanni and Matori, the latter of whom points out their slow progress. In the midst of the scolding, Jessie whispers to Meowth that she has an idea to set the record straight, then she announces the trio's plan to use Z-Moves. Matori recounts that in order to use a Z-Move, a person needs a Z-Ring, which is only obtainable from an Island Kahuna, and she asks Giovanni for a possible lead. Giovanni says the trio should go to Ula'ula Island to meet Nanu, the Island Kahuna and a past acquaintance of his. With that order, Team Rocket heads for Ula'ula Island.
To avoid Bewear interrupting their plans, Team Rocket sets up hand-sewn puppets of themselves, as well as tape recorders that repeat the same sentences. Upon hearing the tape recorders, Bewear doesn't bother to check on Team Rocket and continues to collect fruit from the surrounding forest. Meanwhile, Acerola reads a fairy tale, "The Greedy Rapooh", to Piko and Nene. The story is about a greedy spirit which steals items from people, but is eventually stopped when sealed away by the Island Kahuna. A Shiny Mimikyu nicknamed Mimikins floats around as Acerola reads the book.
Meanwhile, Team Rocket is walking through the forest. Meowth pulls out a bag containing some Mixed Fruits Malasada, a new product and offering to get the trio their Z-Ring. The trio stumble upon the Po Town Police Station. The trio and Wobbuffet quickly get changed into tourist outfits to avoid suspicion. They go on to open the police station's doors, and inside, they uncover a horde of Alolan Meowth. The group immediately spots Meowth's bag of food and resorts to attacking Team Rocket. After a brief squabble, the Alolan Meowth begin eating the Mixed Fruit Malasadas outside, while the disturbance wakes up Nanu. Upon losing their offering to the Island Kahuna, the trio decides to retreat to prepare another present. Nanu queries the group's intentions before stating that the Island Kahuna is on a martial arts training adventure for anywhere between a week to upwards of a year. Shocked, Team Rocket leaves in disappointment.
Meanwhile, Acerola agrees to take Nene and Piko to see the Greedy Rapooh's tomb. Elsewhere, Team Rocket are discussing amongst themselves how to get a Z-Ring. Jessie proclaims the group needs to get a Z-Ring no matter what. In the process, she forcefully puts her foot on an ancient tombstone with a red string around it, causing it to shatter. The Greedy Rapooh emerges from the tomb and it's revealed to be a Gengar, who scares Team Rocket and steals their Darkinium Z.
Acerola, Mimikins, Nene, and Piko stumble upon the scene. Before they can run, the Gengar blocks the fleeing group in their tracks. Acerola blocks Gengar from scaring the two children, and in response, it quickly picks Acerola up and flies into the clouds; Team Rocket and Mimikins follow. Gengar resorts to stealing more items in a frenzy, including a Drampa's Berries, a man's Nugget, and a Blissey's Lucky Egg. It also scares a wild Murkrow and Salandit. Acerola is still clinging on to Gengar, trying to get it to stop causing trouble. Suddenly, Mimikins arrives and engages Gengar in battle. Mimikins's repeated Shadow Claw attacks fail, going through Gengar's body. Gengar throws Mimikins into the air out of frustration, and Acerola jumps off Gengar's back in an attempt to grab it. Gengar's attempt to capture the falling Acerola fails, and she continues to free-fall through tree branches, eventually hitting the ground.
Gengar follows behind and looks over at Acerola as she is holding Mimikins. Gengar suddenly produces all of the stolen goods from its body, surrounding Acerola in gifts to get her attention. Acerola is overwhelmed by the gesture, but is aware that the items are stolen. Team Rocket watches, noticing their Darkinium Z in Gengar's hand. Acerola states that she cannot accept the gifts, as she enjoys her time reading to the children in the library. Gengar goes into a tantrum, bouncing off the forest trees. It then tries to absorb Acerola into its body, but it is interrupted by Jessie's Mimikyu launching a Shadow Ball. Gengar quickly turns its attention to Jessie and Mimikyu, while James retrieves the Darkinium Z from the pile of stolen goods. The Team Rocket trio teases Gengar for losing in front of Acerola and then runs off, with Gengar following in anger. Nanu finds Acerola, asking his niece if she is fine.
Team Rocket stops running and attempts to face Gengar. Meowth's claws grow in anticipation for a Fury Swipes, though Gengar enters Meowth's body and possesses him. Mimikyu attacks, sending Meowth flying. Gengar emerges from his body and then possesses Jessie. In response, James commands Mareanie to use a gentle Knock Off against Jessie. The attack lands, and Gengar emerges from Jessie's body with tears in its eyes. As Meowth and Jessie quickly recover, Acerola, Mimikins, and Nanu stumble upon the trio. Nanu comments on the trio's skill before gifting them a Z-Power Ring. James places it on his wrist and has Mareanie perform Black Hole Eclipse for the first time against Gengar, defeating it.
Acerola reveals that Gengar must have been lonely, hence why it kidnapped her and offered all of the stolen goods to her. This assumption turns out to be correct, for Gengar begins twirling around with her, and the two decide to become friends. Nanu tells Gengar that if it continues to misbehave, he will reseal the Pokémon into a tomb. In the process, he reveals that he is the Island Kahuna, much to Team Rocket's disbelief. Jessie angrily reveals Team Rocket's true motives for coming to see him. Nanu confirms that he has a personal connection with Giovanni and is aware of Team Rocket. Meowth demands that they want a Z-Ring, and so, Nanu decides to let the Team Rocket trio keep the Z-Power Ring as repayment for looking after Acerola. Jessie and James's attention turns to Acerola and her flying Mimikyu. Acerola states that Mimikins is an actual ghost, upon which Mimikins gives Jessie a Mimikium Z. Jessie, James, and Meowth are left ecstatic over achieving something beyond their intended goal.
Meanwhile, Ash, Rotom, Pikachu, and Poipole are aboard a ship headed for Ula'ula Island and Ash's third grand trial.