Evolving Research! (Japanese: 海あり谷あり！ポケモン進化大特訓！！We Have a Sea and We Have a Valley! Great Intensive Pokémon Evolution Training!!) is the 106th episode of the Sun & Moon series, and the 1,045th episode of the Pokémon anime. It first aired in Japan on January 27, 2019, in the United Kingdom on May 30, 2019, and in the United States on June 1, 2019.
As our heroes continue their research projects, Sophocles wants to help Charjabug evolve. The pair set off to Vast Poni Canyon and encounter Horacio, who wants his own Charjabug to evolve first. But when Horacio ends up in danger, Sophocles’s Charjabug springs into rescue mode and evolves into Vikavolt!
Meanwhile, Lana has her heart set on training, but she’s disappointed because her mentor, Ida, is about to depart Poni Island. Still, Popplio and Sandy have fun playing with Ida’s Primarina, and when Lana decides to show Ida what she’s capable of, Popplio evolves into Brionne! As congratulations, Ida gives Lana her own Primarium Z and encourages her to continue training.
At the Poni IslandPokémon Center, everyone declares their plans to continue working on their individual papers. Ash encounters Hapu again, following her declination of his request to battle, and she explains that she arrived to deliver everyone some of her homegrown Poni radishes. Hapu then asks what everyone is planning on doing and Sophocles replies that he is heading to Vast Poni Canyon to hopefully evolve his Charjabug. Kiawe queries his friend's logic, but Hapu quickly dismisses Kiawe's doubts and adds that old stories state that Charjabug are known to evolve around Vast Poni Canyon. Ash and Kiawe are excited and decide to travel with Sophocles to watch Charjabug evolve.
Lana sees Ida and greets her as she pulls into Seafolk Village. She then formally introduces Sandy to Ida and her boyfriend Kanoa. Afterwards, she learns Ida's Brionne evolved into a Primarina. Ash and the others join Lana on the pier and are also amazed by Primarina. Rotom goes on to scan it into its system before Ida showcases Primarina's melodic water balloon display. Lana is enchanted by Primarina's control and asks Ida to train her, though Ida is seemingly unsure. Kanoa then spots Hapu amongst the children and congratulates her on finally making some friends, but Hapu tells him that Ash and his classmates are simply acquaintances. Ida informs everyone that she and Kanoa will be setting off the following morning to entertain crowds in other regions with their water performances.
Later, Ash, Kiawe and Hapu travel with Sophocles to Vast Poni Canyon, while Mallow and Lillie accompany Lana as she trains with Ida on Poni Beach. During their travels through Vast Poni Canyon, Ash and the others face off against several unruly wild Pokémon. Sophocles battles a wild Golduck with Charjabug, who uses Discharge, but Togedemaru jumps in to absorb the attack and strikes Golduck instead. Sophocles scolds Togedemaru, but she simply bounces around in excitement. The group soon approaches a cave entrance, and as Sophocles searches for his next challenge, he then spots Horacio with his brothers Dana and Yansu. Ash initially doesn't recognize the trio, but Sophocles tells him that they competed against them in the Charjabug race. Like Sophocles, Horacio is hoping to evolve his Charjabug into a Vikavolt. Horacio then declares that he will be the first to evolve his Charjabug, and adds that he simply needs to obtain a "Bug Stone". Rotom scans its system and declares that the item doesn't exist, but Horacio insists it does and admits that his father paid good money to obtain the top-secret information. Sophocles then challenges Horacio, and they agree that whoever evolves their respective Charjabug first, without any assistance, will win. Sophocles leaves Togedemaru in Ash's care as he ventures deeper into the Vast Poni Canyon.
Horacio walks ahead, though Sophocles soon struggles in the dark cave system because of his fear. His concerns are quickly eased as Charjabug offers some of its electricity to make a bright light. Sophocles is touched by the gesture, he then remembers he has a light on his device and turns it on instead. The strong magnetic field is disorientating Sophocles GPS system, and the pair soon come to a stop in front of a cave wall. Later, Sophocles approaches a swarm of Golbat, but Charjabug quickly steps in front to intervene. Charjabug tangles the Pokémon in a String Shot and follows up with a Discharge attack, allowing it and Sophocles to continue on their way. There, the pair spot Horacio and his Charjabug begin to cross a rope bridge. Sophocles calls out to Horacio, but the bridge snaps, leaving Horacio and his Charjabug desperately holding on. Sophocles is stares in shock, then suddenly his Charjabug evolves into a Vikavolt.
With its new wings, Vikavolt zips over and rescues Horacio and his Charjabug. Horacio is still set on grabbing the so-called "Bug Stone", and Sophocles's Vikavolt flies over and retrieves an odd green item from a nearby shrine. Horacio places it on his Charjabug several times, but it doesn't evolve. Sophocles tells Horacio that the canyon's special magnetic field actually triggered his Charjabug to evolve. Kiawe and Ash become concerned and decide to rush in to find Sophocles. As they are about to enter the cave they are startled by a swarm of fleeing Golbat. Sophocles and his new Vikavolt soon emerge from the cavern's darkness to greet their friends. Horacio, on the other hand, exits the cave looking distraught from his defeat. He declares that he will train harder and will challenge Sophocles to a Vikavolt race next time they meet. Before he and his brothers set off, Horacio falls off a ledge in his haste to leave the area.
The boys and Hapu later return to the Pokémon Center by nightfall, and in time for Ida and Kanoa's farewell party. Mallow's cooking helps to make the dinner a spectacular event, and for the night's entertainment, Ida has her Primarina perform a beautiful rendition of Oceanic Operetta. The Z-Move encourages Lana, and she soon rushes off to train Popplio further.
The following morning, Ash and his classmates wait on a pier as Kanoa and Ida are about to set off. Mallow then notices that Lana is missing, but she soon arrives on the scene. Lana has Popplio make a water balloon, and with some singing the bubble continues to grow to epic proportions. Unexpectedly, Popplio begins to glow in a blue light and evolves into Brionne. In its new form, Brionne continues to control the water balloon before bursting it into a shower of sparkles. Ida is impressed by Lana and Brionne's skills, and she goes on to offer Lana a Primarium Z. Lana is initially hesitant, but Kanoa assures her that this Z-Crystal is another one that he found on the seafloor. Lana happily accepts the Z-Crystal as Ida wishes her all the best for the future. Kanoa and Ida soon set off on their journey aboard their Steelix vessel while Ash and his classmates wave them off.