Ash is running to school, excited about today's field trip to Akala Island. Inside the school grounds, Ash asks Rotom what kind of Pokémon live on Akala Island but as Rotom does a search, Ash is hit by a Tauros which sends him flying. Charizard lands in front of Tauros and restrains the angered Tauros, and Sophocles explains that Tauros had become startled when Charizard had landed. Charizard struggles with Tauros until a Midday Form Lycanroc jumps down in between them. A lady arrives and after greeting them, goes over to the Tauros and calms it down, before giving it a kiss to everyone's shock. The lady then goes over to Charizard, complimenting it on doing a good job and gives it a kiss as well. Kiawe goes over and greets her, calling her by the name Olivia. As Ash asks Kiawe if he knows her, Kiawe introduces the lady as Olivia, Kahuna of Akala Island.
Inside the classroom, Olivia comments that she will be in charge of the field trip and starts to get something out for the group, but trips instead. After picking herself up in embarrassment, she brings out some jewelry, and hands one to each student. As she approaches Ash, who doesn't know what to think about the jewel he had received, Olivia reveals her Z-Ring. Ash is excited to see her Z-Ring which contains a Rockium Z, and Olivia asks Ash if he is taking on the island challenge which Ash confirms. Olivia then tells the group to grab their stuff to leave, only to collide with Samson Oak who arrives in the classroom.
Outside, everyone has brought out their Pokémon and Olivia is amazed at their facial expressions, as she can tell that they are all very much loved. The group note that none of their Pokémon have their guard up against her, and not even Litten is guarded around her. Kiawe also mentions that during his grand trial with Olivia, Turtonator had let its guard down with someone it hadn't known and that she must truly have a special power. Olivia then asks the class to tell her more about their Pokémon.
Later, Olivia finds herself crying having learnt that Litten had gone through a lot before it had met Ash. Lillie hands her a handkerchief to dry her eyes which she does, and then blows her nose, much to Lillie's dismay, which Lana finds interesting. Olivia then tells everyone that their Pokémon are all lucky to have such great partners. Also, as a reward for telling her about all of their Pokémon, Olivia says she in return will tell them about Akala Island. As she begins her talk on Akala Island, she asks the group if they know who the Guardian of Akala Island is. In reply, Ash states that it is Tapu Lele, and then Olivia describes that Tapu Lele is known to scatter its glowing scales from time to time, and that whoever the scales touch will be healed. Ash, remembers his encounter with Tapu Lele realizes that this is why his injuries had been healed. After her talk, Olivia tells the group to get ready as they head to Akala Island. Down at the port, a cruiser is waiting to take them and Olivia jumps aboard, only to trip once more.
Out on the ocean, Sophocles is looking through his phone, and finds a picture of Kiawe, Sima, Rango and Mimo in an Akala Island guidebook. Mallow, looking on, spots a picture of a nervous Kiawe. As the boat continues to head to Akala Island, Lana spots something jump out of the water. Professor Kukui and Olivia decide to make a detour to investigate, and they approach a group of Dragonair leaping out of the water. One of the Dragonair uses Rain Dance much to the amazement of the class. Olivia comments that their field trip learning has just begun. As they make their way to Akala Island, they are able to spot various Water-type Pokémon, including a Slowpoke evolving into a Slowbro.
Later, Olivia looks over the railings in search for other Pokémon, but ends up falling over and into the ocean. Unfazed, Olivia invites the others to join her, and so Ash and Pikachu jump in to swim. The three of them swim underwater, looking at all the Pokémon, but soon notice some splashing near some rocks which they decide to investigate. Wondering where Ash, Olivia and Pikachu are swimming off to, Professor Kukui steers the ship over to them. Ash, Olivia and Pikachu reach the rocks and find a Wailmer trapped in the rocks. Rotom joins them and Ash tells him that Wailmer is stuck. Alarmed, Rotom heads back to inform the others while Ash, Olivia and Pikachu swim towards Wailmer. They try to pull Wailmer free, but the effort sends Olivia underwater. Here, she spots a Bruxish nearby and realizes that the Bruxish is responsible for this. After surfacing, Olivia warns everyone about Bruxish's powerful Psychic power and they all get back on board. To help the Wailmer, Olivia asks Lycanroc for its assistance. Despite its weakness to Water, Lycanroc jumps into the air and uses Accelerock on the nearby cliff before safely returning to the boat. The attack causes rocks to fall into the sea, freeing Wailmer. However, since Wailmer is still under Bruxish's Psychic power it starts to sink. Bruxish then jumps out of the water to scare them before emitting a loud sound. Olivia tells Lycanroc to use Rock Slide which hits Bruxish who soon flees.
Quickly, Olivia, Ash, Kiawe, Lana and Popplio jump into the ocean to help the sinking Wailmer. Once they reach Wailmer, Lana has Popplio form a balloon which helps float Wailmer back up to the surface. Rotom notes that Wailmer is weak and so Lillie goes to grab some medicine. Mallow and a reluctant Sophocles jump into the water to help. Popplio then pops the balloon and everyone's combined efforts prevent Wailmer from sinking. Wailmer panics but Olivia reassures it that it will be fine. Lillie quickly arrives with the medicine and throws it to Olivia. Olivia then feeds Wailmer the medicine and the Psychic power loses its effect. Back on the boat, everyone watches Wailmer swim off and Kiawe tells Olivia that she really is amazing. At that moment, her leg cramps from all the swimming, causing her to fall over again. They arrive on Akala Island and go to the Pokémon Center for the night where the group are greeted by Nurse Joy, Blissey and Comfey.