One day at the Pokémon School, Pikachu, Steenee, Popplio and Togedemaru have a race around the classroom. With Pikachu in the lead, Ash, Mallow, Lana and Sophocles cheer on their Pokémon. As the Pokémon race around the tables, Togedemaru trips, causing Popplio and Steenee to fall. Pikachu reaches the finish and jumps into Ash's arms. Professor Kukui arrives at that moment, noting how well everyone is doing with their Pokémon. Professor Kukui announces that today, they'll be trading their Pokémon partners, much to their surprise. With everyone sitting at their tables, Professor Kukui clarifies that they'll only be changing partners temporarily so that they can get a better understanding of the nature of different Pokémon. While the classmates' reactions to Professor Kukui's announcement vary, Lillie notes that this will be a great opportunity for her to play with Pokémon other than Snowy. Professor Kukui brings out six sticks and states that those who select matching colored sticks would be trading their Pokémon.
Lillie and Ash end up selecting a red-colored stick meaning they will be trading Snowy and Pikachu. Meanwhile, Mallow and Sophocles trade Steenee and Togedemaru, while Kiawe and Lana exchange Turtonator and Popplio respectively. Professor Kukui informs them that the trade will continue until the following Monday.
Komala rings the bell, signalling the end of school. As the others set off with their newly traded Pokémon, Lillie's limo driver arrives and Pikachu jumps in the car. Lillie then attempts to enter the car but gets a little nervous of Pikachu. Sensing this, Pikachu moves further along the seat, allowing Lillie to get in. The car drives away with Ash waving goodbye.
Later, Ash and Snowy arrive at Professor Kukui's house, where Ash calls out Rockruff and Litten before opening his backpack and waking Rowlet up. Ash tells his Pokémon to be nice to Snowy.
At Lillie's mansion, Hobbes greets Lillie who informs him that they have a guest and Hobbes is surprised to see Pikachu with her. Inside, as Pikachu eats macarons, Lillie attempts to approach Pikachu. However, she becomes easily startled as Pikachu turns towards her. Lillie tries again and reaches her hand out to Pikachu. But when Pikachu becomes happy, Lillie is startled once more. Despite her failure, Lillie becomes determined to touch Pikachu knowing that if she can touch Snowy, she can touch Pikachu. In the garden, a collection of Pokémon are playing and Lillie tells Pikachu that he can play as much as he wants. As Pikachu plays with Petilil and Bonsly, Lillie makes notes, having decided to start with observation.
At the Aina's Kitchen, Abe puts a plate of food out ready for Mallow to serve to the customers. The customers note that Togedemaru is cute and invites Togedemaru to play with them. Excited, it begins to roll around, causing trouble by knocking over customers and tables. Mallow tells Togedemaru that it can't play in the restaurant, before getting knocked over herself. Outside Sophocles' house, Sophocles has placed Steenee on the big wheel and attached a device to Steenee's head for research and asks Steenee to try and run. However, Steenee doesn't understand and instead becomes interested in a shrub of flowers. Sophocles notes that it would be easier if Togedemaru was here. At Lana's house, Harper and Sarah are overjoyed at seeing Turtonator, but Lana warns them to be careful. Down at Kiawe's family farm, Kiawe wonders what to do as he isn't good with Water-type Pokémon. Mimo runs over to Popplio, inviting it to play with her. Kiawe then suggests her to get some Moomoo Milk and take it with Popplio. As night falls at Professor Kukui's house, Ash tries to get Snowy to come over to him but Snowy walks off. As Ash tries again, Snowy freezes him with Powder Snow. Professor Kukui announces that dinner is ready and Ash collects four bowls of food to give to Rowlet, Litten, Rockruff and Snowy. However, Snowy isn't interested in the food which Rotom finds strange as this is Snowy's favorite food.
That night, Sophocles is having trouble sleeping without Togedemaru. Sensing his problem, Steenee hops into bed with him and releases its Sweet Scent to help put Sophocles to sleep. The next day at the Aina's Kitchen, Mallow is cleaning the windows but falls when Togedemaru knocks into her. Mallow asks Togedemaru to stay still but Togedemaru continues rolling around in a ball, knocking into a mop and bucket. Togedemaru becomes all wet and the wipes become stuck on its spikes. Frightened, Togedemaru continues rolling around in a ball around the restaurant leaving the floor all sparkling clean. Surprised at the speed of the cleaning, Mallow tells Togedemaru to continue rolling until it is complete. At Kiawe's farm, Mimo rushes to Kiawe, informing him that the Tauros are fighting. Kiawe goes to have Turtonator stop them before realizing that he doesn't have Turtonator with him. Instead, Popplio approaches the Tauros and Kiawe warns Popplio to be careful. However, Popplio releases one of its balloons which splashes the Tauros. Realizing that Popplio is trying to help, Kiawe has Popplio create a bigger balloon. Popplio creates a big balloon that pops just above the Tauros' heads, splashing them with water and calming them down. Popplio then uses Bubble Beam to create a bubble bath for the Tauros, allowing them to calm down further. Outside Lana's house, Harper and Sarah are jumping on Turtonator's back. Before Lana can warn them, the twins touch Turtonator's spikes, causing it to explode. Although Harper and Sarah are covered with ash, they are still overjoyed. Lana gets a brush out and scrubs Turtonator's back without touching the spikes. The twins come to help out as well, and working together, they wash Turtonator's back.
At Professor Kukui's house, Ash suggests that they all go for a walk remembering that Lillie mentioned that Snowy enjoys going for a walk. They walk to the marketplace where they meet Anela, who is pleased to see Litten doing well and offers them berries to eat. As Litten, Rowlet and Rockruff enjoy their meal, Anela encourages Snowy to join. Litten grabs a berry and takes it over to Snowy. With everyone's encouragement, Snowy slowly begins to eat the Sitrus Berry. Heading down to the beach, Ash tells Snowy that they always train together and asks if Snowy wants to try as well. Ash has Litten use Ember and mentions that training relieves stress. Snowy then uses Powder Snow on the rocks, freezing the rock and waves which Ash finds amazing. At Lillie's mansion, Lillie passes Pikachu a bowl of food to eat but when Pikachu approaches the bowl, Lillie becomes scared. She wonders how Ash managed to befriend Pikachu and remembers that Ash loves to battle alongside Pikachu. Outside on the battlefield, Lillie tells Hobbes not to hold back. Lillie tells Pikachu to use Quick Attack but Hobbes' Oricorio successfully dodges it. It then uses Revelation Dance which hits Pikachu. This is quickly followed by Teeter Dance causing Pikachu to become confused. Hobbes then orders Oricorio to use Double Slap which hits Pikachu. Lillie becomes worried as Hobbes orders another Double Slap which sends Pikachu flying. Lillie remembers that the key to battling is the trust between Trainer and Pokémon and realizes that if she doesn't have trust of confidence, then Pikachu will lose. As Pikachu's partner right now, she realizes that she will need to give it her all. Pikachu shows that it trusts Lillie so Lillie orders another Quick Attack which hits Oricorio. She then commands Pikachu to use Thunderbolt which hits Oricorio, knocking it out. Lillie is stunned that they won and excitedly runs towards Pikachu before hugging it. Lillie and Pikachu then both realize that she is actually touching Pikachu and they continue their hug. Hobbes cries at the sight.
At school, the Trainers are reunited with their Pokémon. Professor Kukui notes that they had all really learnt a lot from trading partners. Sophocles agrees and brings out Malasadas reproduced from Steenee's aroma. As the class help themselves to the Malasada, Mallow asks Lillie if she managed to become Pikachu's friend and in response, Lillie allows Pikachu to climb onto her shoulder. Lillie then says that she'll manage to touch more and more Pokémon one step at a time. Professor Kukui asks how Ash did with Snowy and Ash replies that he trained with Snowy. Ash then asks Lillie for a battle where he'll use Snowy and she'll use Pikachu. Outside on the school's battlefield, they prepare to have their battle.