Having arrived at Paniola Town on Akala Island, Ash and his friends get ready for their first lesson with Olivia. She brings them to a barn full of Stoutland, explaining that the town's Stoutland are known for their ability to find hidden treasures. As a result, the class will involve using the Stoutland as Ride Pokémon in a treasure hunt. Professor Kukui instructs the class to choose a Stoutland they bond the best with. Ash is excited over all of the Stoutland, and one by one the others select their own Stoutland. Lana approaches a particularly disagreeable Stoutland, who Olivia says has the wildest personality of all the Stoutland and hasn't quite fully developed its tracking abilities. Peering into its clear eyes, Lana decides to go with the surly Stoutland. Ash bonds with a friendly Stoutland that pounces on him and licks at his face, reminding him of the Stoutland that Litten befriended.
Outside the barn, Professor Kukui informs the group that they are allowed to search anywhere they please, but must return at the sound of a bell so their finds can be evaluated. Ash and Kiawe are first to set off, declaring a rivalry to find the best treasure. Mallow decides to head for the jungle, while Sophocles asks his Stoutland to head for a rocky area. After struggling with her Stoutland when it throws her off its back, Lana manages to set off as well, leaving Lillie as the only one who hasn't departed. Despite changing into a rider's outfit, Lillie is completely intimidated by Stoutland and unable to mount it.
Ash's Stoutland enthusiastically leads him into the forest, where it unearths a Red, Blue, and Green Shard in turn, licking Ash's face after each find. As Kiawe investigates a coastal cliff, Mallow is excited to find several Tiny Mushrooms and Big Mushrooms, having used them before in her cooking. Sophocles looks up data about rare finds on his computer, discovering that a meteor fell on Akala Island a long time ago, breaking apart into many valuable fragments, and decides to make looking for those his priority. Lana continues to have trouble with her Stoutland as it opts to snack on Sitrus Berries at an orchard while Lillie remains unable to get on her Stoutland.
By the first bell, everyone returns to the barn so Olivia can appraise their finds. Ash's Shards net him 15 points, but he is quickly disappointed when Olivia gives Mallow 20 points for her mushrooms. Neither Lana nor Sophocles have anything to show; Lana is dejected while Sophocles is confident that his plans will allow him to catch up. Kiawe reveals his find of a Skull Fossil which earns him 100 points, stunning Ash at how far ahead Kiawe is.
The second leg of the hunt begins with the class heading back to where they searched earlier. To Ash's disappointment, his Stoutland merely unearths a Yellow Shard. Meanwhile, Lana's Stoutland chooses to take a nap after more snacking, prompting Popplio to offer its aid in hunting for treasure instead. Lana follows Popplio as it runs ahead, but is startled when Popplio is knocked back. A wild Garbodor reveals itself, angered by Popplio's intrusion, and begins attacking. Lana retreats, but after tripping over a rock, Popplio decides to stand firm and fight. Despite Lana ordering a Bubble Beam, an attack by Garbodor bursts through and heavily damages Popplio, forcing Lana to run away. Reaching her Stoutland and realizing that it shows no signs of waking up, Lana declares that she will shield both Stoutland and Popplio as Garbodor readies another attack. This finally rouses Stoutland, who lunges at Garbodor and defeats it with Giga Impact. Lana thanks Stoutland, and the Big-Hearted Pokémon asks her to climb aboard.
As the others continue their respective searches, Lillie remains terrified of her Stoutland. Olivia and Professor Kukui encourage her, with Professor Kukui reminding her of how she eventually became able to touch Snowy and Pikachu. This causes Lillie to remember her own wish to be able to touch more Pokémon, and she becomes determined. At the same time, Ash's Stoutland has moved to a rocky area, stopping at a large boulder. Ash decides to bring back the boulder as a treasure, but is startled when the boulder glares back at him, and he flings it away. Taking a closer look, Ash vaguely identifies it as a Geodude, and Rotom Pokédex offers up the information on Geodude's Alolan variant. Ash decides to catch the Geodude, and orders an Electro Ball from Pikachu, but as the Alolan Geodude is also an Electric type, it fails to deal much damage. Ash orders an Iron Tail, which proves successful, but as he throws a Poké Ball at Geodude, it retaliates with Thunder Punch, sending the ball ricocheting to Ash's face before escaping, much to Ash's disappointment.
As the second and final bell rings, Lana worriedly informs her Stoutland that they have run out of time with nothing to show, but her Stoutland presses on and brings her to a cave to unearth something. This causes Lana to be the last of her class to arrive for the appraisal. Ash's Yellow Shard gives him an extra five points, and Ash laments that he's already lost to Kiawe. Mallow reveals a large Lansat Berry as her find, which nets her 75 points for its rarity and size. Sophocles shows off his Star Piece, which Olivia identifies and curates for the class, giving Sophocles 150 points. Moving on to Lillie, Professor Kukui points her out as Lillie carefully, but confidently climbs aboard her Stoutland, to the amazement of her classmates. After everyone congratulates Lillie on overcoming her fears, Olivia reveals that Kiawe has unearthed a Plume Fossil, earning him 200 more points and disappointing Sophocles.
Kiawe declares himself the winner until Mallow points out that Lana hasn't been appraised yet. Lifting up the cloth covering Lana's find, Olivia identifies Lana's treasure as a sample of Z-Ring ore, earning Lana 500 points and placing her in the lead. As everyone congratulates Lana, Olivia adds that she intends to make the ore into a proper Z-Ring and give it to Lana.