Officer Jenny is shocked to see the arrival of the Red Buns Passimian on Melemele Island, while several Machamp lie unconscious on the sand. Meanwhile, Ash and his Pokémon, in the midst of doing chores, make their way through the Hau'oli City market. While there, the group encounters Anela, who is surprised to see that Litten has grown up a lot. Rotom corrects her, stating that Litten has since evolved into a Torracat. She rewards the group with Sitrus Berries. As the Pokémon are busy eating their treat, Ash is hit by a piece of fruit after a group of Passimian were busy playing and failed to catch it. The Passimian mistakenly grab Rowlet, who resembles the fruit's color and round shape. Ash shouts out, causing the Passimian trio to pause. Anela explains that the Pokémon are Passimian, and that they tend to live in the forest and play with fruit. With Rotom's internal data, Ash picks up the Passimian's discarded fruit and quickly makes a trade for Rowlet's return. As he waves the trio goodbye, Ash turns around to find an intimidating and physically larger trio of Passimian standing behind him.
Ash assumes the two groups are friends, before he is bowled over and caught by the first group of Passimian. One, from the same group, runs past two of the opposing members but is quickly knocked back by the third one, who has a scar around its eye. One of its teammates picks up the fruit, though it quickly finds itself surrounded. Even so, it manages to make a successful pass, though its teammate fumbles, dropping Ash in the process, and the fruit bounces directly into Ash's arms. The scarred Passimian quickly snatches the fruit from Ash's hands, yelling in victory, and the trio soon walks off. While the green Passimian are disappointed by the loss, Officer Jenny arrives on the scene and has the unconscious 'Tiny', the boss of the green Passimian, escorted to the Pokémon Center.
Nurse Joy emerges from the recovery ward and alerts Ash, Jenny, and the other two Passimian that Tiny will make a full recovery by tomorrow. She then asks if the Passimian are the Melelmele Greens that live near Iki Town. Jenny confirms this and adds that the other Passimian team is from Akala Island. Called the Red Buns and led by 'Claw', they are notorious for their violence, which forced Jenny to station more guards to avoid more conflict.
The next day, at the Pokémon School, Ash tells his classmates about the previous day's events. Kiawe believes the Red Buns were the ones who rampaged through his family's ranch one time. Sophocles is perplexed by their arrival to Melemele Island for a fruit. Professor Kukui enters the classroom and claims that the Passimian may be attempting to decide the boss of their groups. He explains that each of the Passimian troops take care of a special fruit, and that whoever holds it also has authority over the troop. Ash quickly realizes that Tiny lost its leadership status, and hopes it is doing okay.
Later, Officer Jenny escorts Ash through to the Melemele Greens nest, and commends Ash for his concern for Tiny. They quickly come upon a group of fifteen Passimian and observe them playing, grooming each other, and eating fruit. Ash is glad to see Tiny and its comrades are doing fine, despite their disappointment over the loss. Suddenly, the Red Buns troop enters, stopping the Melemele Greens from socializing. Claw places the special fruit into a hanging vine basket, taking its place as the group's new leader. Jenny informs Ash that the Red Buns were reportedly attacking other troops on other islands. Ash is infuriated by Claw's attitude as the Melemele Greens cater to its new leader's every whim. Ash's attention turns to bolstering the confidence of Tiny and its troop, though the trio remains glum.
The next day at school, Kiawe is startled by Ash and Pikachu when they drop in front of him from the ceiling. Sophocles explains that Ash has been behaving strangely all morning, as Ash continues jumping and running on all fours. Kukui enters and is instantly impressed by Ash's acting. He adds that Ash hopes that, by acting like Passimian, he will able to communicate with them effectively. Over lunch, Ash's impersonation continues; he even steals Rowlet's food in the process. Seeing this, Lillie gets an idea, and with Mallow and Lana's assistance, the three girls make Ash a Passimian costume complete with complementary makeup. Ash is overjoyed by the finished product, and the students quickly make their way over to the Melemele Greens.
Ash's appearance does nothing to impress or promote a response from the somber Melemele Greens. Suddenly, a Passimian tugs at Ash's tail, and Ash offers it the Berry. The Passimian eagerly accepts, then steps backwards and throws the Berry at Ash. Realizing that Passimian wants to play, he throws the Berry back at it. This quickly motivates the other Melemele Greens, amazing Ash's classmates in the process. Ash gains possession of the Berry once again, this time pitching it quite far. With a helping hand from some its friends, Tiny is launched into the air and manages to catch the rogue throw, demonstrating some incredible acrobatics in its landing. However, the Red Buns' return and Claw takes Trip's place. Just as Claw is about to grab a handful of fruit, Tiny throws a Sitrus Berry at its hand, challenging Claw and its troop. The two agree to battle for leadership, though the other Passimian are less confident. Ash offers his assistance, which helps to bolster Tiny's confidence.
The two rival troops are staged on the beach, with Ash making Tiny's troop a team of four against the Red Buns' three members, while Ash's classmates and the other Melemele Greens watch on. Claw throws the special fruit into the air, and it soon lands in-between the rival team, sending them into a scurry for possession. The Red Buns quickly grab the fruit, throwing it to another member. While one of the Melemele Greens holds onto one the opposition's waists, it is dragged along as the fruit is passed to Claw. Claw manages to jump through the Melemele Greens two-player defense, kicking one in the stomach. Ash manages to catch Claw's trick shot, sliding across the sand as a result. This sets off a chain of successful throws for the Melemele Greens, returning to Ash's possession soon after. Ash remembers the Red Buns' strategies from earlier on, and repeats their technique. He manages to run through two players, though he trips and the fruit rolls directly into Claw's hands. The tide of the game seems to have changed again, with Ash's friends fearing the worst.
Ash suddenly has an idea and passes on instructions to his teammates as the game continues. Tiny is hoisted into the air and grabs the fruit. The Red Buns charge ahead, though Tiny runs for a nearby tree. It jumps from the trunk, bouncing onto one the Red Buns' shoulders before somersaulting over the other two players and landing with the fruit still in its hand. As Tiny prepares to pass, it finds its teammates cornered by the Red Buns. Another Melemele Greens enters the game, which encourages the rest of the troop to join the beachside skirmish. The Red Buns quickly find themselves outnumbered. After a series of throws, the game ends, with the Melemele Greens asserting leadership over their troop, much to the Red Buns' embarrassment. As an act of thanks, the fruit is thrown to Ash before he is hoisted up onto the cheering Melemele Greens, who make their way to their nest. Ash is taken aback by the gesture as the troop continues on, with Lana declaring that Ash is the new troop leader, much to everyone's shock.
At night, Kukui calls Ash's Pokémon back inside for dinner, but they continue to wait for his return on the porch. Kukui assures them that Ash will return soon. All of a sudden, Ash proudly announces his return while still being held up by an even larger Passimian troop.