While riding around the Orange Islands on his Lapras, Ash finds a mysterious message in a bottle, which leads the gang on a new adventure. Ash, Misty and Tracey travel to Sunburst Island, which is famous for its artists and glassblowers. They meet a struggling young shopkeeper who's seeking inspiration from a legendary crystal Onix. Having been unable to find this special Pokémon, the shopkeeper turns to our heroes. With Tracey and his observational Pokémon on board, they set out to fire up a new friend's creative drive!
While riding around the Orange Islands on his Lapras, Ash finds a message in a bottle from Marissa of Sunburst Island who is looking for someone who knows about a Pokémon called the Crystal Onix. Tracey is aware of the rumors and the mystery leads the gang on a new adventure. Ash and his friends travel to Sunburst Island, which is famous for its artists and glassblowers. They overhear an argument between a rival shopkeeper and a young girl, and go to intervene. The young girl is revealed to be Marissa, the same person who wrote the message in the bottle. They meet her older brother, a struggling young shopkeeper named Mateo, who’s seeking inspiration from the legendary Crystal Onix. He smashes one of his Pokémon statues out of frustration and complains they are lifeless compared to his grandfather's works. Mateo tells the group that his grandfather once saw the actual Crystal Onix and shows them his grandfather's Crystal Onix statue. Having been unable to find this special Pokémon, Ash and his friends decide to help him in his search.
Team Rocket arrives on Sunburst Island as well, and are in awe of the glass shops. Jessie and James start picking up various pieces and admiring them. Meowth yells at them to knock it off, causing Jessie and James to break the glass items they were holding. The shopkeeper hears this, and tells them about the "You break it, you bought it" rule before he puts them to work, since they don't have the money to pay him back for the items they ruined. While they're chopping and carrying wood, they overhear the shop owner and another employee mock Mateo for searching for the Crystal Onix. Team Rocket becomes interested and they leaves in search of it.
Tracey sends out Venonat to help find the Crystal Onix. Mateo holds up the statue of the Crystal Onix his grandfather sculpted and Venonat scans the image. The group is lead to a series of rocks that are shaped like the body of an Onix. Disappointed, Tracey recalls Venonat and sends out Marill, noting its large and sensitive ears may prove useful. Tracey plays Marill a recording of Onix's cry and Marill quickly detects something. Marill leads them to a body of water and points across the water to a small island with a cave. The water begins to part which reveals a land bridge that leads to the cave. They fall into one of Team Rocket's pitfall traps. After reciting their motto, Team Rocket run off to find the Crystal Onix. Ash and friends climb out of the hole and set off after them. Once they get to the opening of the cave, they discover Team Rocket got caught in their own traps. Misty refuses to help them and they all enter the cave.
At the end of the cave they come across a lake. Marill dives in this lake, its tail bobbing above the surface. Marill hops out of the water and then the Crystal Onix bursts out. Mateo calls on his Cloyster, thinking it has the type advantage. However its Water Gun attacks prove useless. The Crystal Onix retaliates and in one headbutt Cloyster is knocked out. Team Rocket shows up, free from their traps. Jessie and James send out Arbok and Victreebel in attempt to catch the Crystal Onix. Ash and Misty send out Pikachu and Staryu to counterattack. Staryu and Pikachu attack Team Rocket, then the Crystal Onix smacks them in to a blast off. Seeing as Cloyster's water attacks proved to be useless against the Crystal Onix, Mateo sends out his Charmeleon. Charmeleon dodges a Rock Throw and uses Flamethrower which engulfs the Crystal Onix in flames. Onix glows a brilliant red and Charmeleon fires its Fire Spin* attack. Mateo and the Crystal Onix stare at each other. In the moment Mateo sees multiples of himself in Onix's glass facets. The Onix then faints into the water. Ash calls out for Mateo to catch it, but Mateo says he doesn't need to, he has found inspiration through the Crystal Onix. The Crystal Onix dives back into the water. Back at his shop, Mateo and Charmeleon are busy making a glass figurine while Marissa is happy to see her brother working again. Ash and his friends wave goodbye to Mateo and Marissa, wishing the pair all the best with their glass shop. On their trek to the water, Ash admires Mateo's handcrafted and lifelike glass Pikachu sculpture.