After a battle with Hobbes in which she managed to defeat his Oricorlo, she found herself able to touch Pikachu when she gave him a hug in celebration. At first, Lillie's fear gave her trouble getting closer to Pikachu. Pikachu was given to Lillie while Snowy went to Ash. In The Ol' Raise and Switch!, Professor Kukui tasked everyone with switching their partner Pokémon with somebody else. At the end of the episode, Lillie arrived at the beach, where Ash and Gladion had held a battle, and became annoyed by the fact that her brother took off so early without saying goodbye. Lillie was troubled by how much more cold and distant Gladion appeared to be from the last time Lillie saw him six months ago, but Ash reassured her that Gladion was still a good person, reminding her of her brother's words of encouragement. Gladion was surprised by the fact that Lillie was able to touch Pokémon again and told her to treasure her Vulpix. Lillie was reunited with her brother in A Glaring Rivalry!. From that point on, Lillie was okay with holding Snowy, though she still froze at contact with other Pokémon. After that, Team Rocket was frozen by Snowy's Powder Snow and taken away by Bewear. When Snowy was blasted off a rooftop by Mareanie's Sludge Bomb, Lillie leapt off after it and caught it in her arms. Eventually they were confronted by Team Rocket, and Snowy used Powder Snow to protect Lillie from Mareanie. Though her fear of touching Pokémon initially persisted, she spent time bonding with Snowy. Lillie officially caught the Vulpix, which she nicknamed Snowy, in Getting to Know You!, making her a Pokemon Trainer like the others. After several failed exercises at petting Ash's Pikachu, Rowlet, and Rotom, Lillie was able to touch the Egg when she instinctively shielded it from a wild Salandit. In Lillie's Egg-xhilarating Challenge!, Lillie agreed to watch over a newly discovered Pokemon Egg from Mount Lanakila for a class assignment, seeing it as an opportunity to finally overcome her fear of touching Pokémon. She and the other classmates saw Tapu Koko for themselves when it appeared to challenge Ash and Pikachu to a Pokemon battle, during which Lillie advised Ash about Tapu Koko's techniques. In The Guardian's Challenge!, after Ash enrolled in the school and showed his new classmates the Z-Ring he received from Tapu Koko, Lillie explained the guardian's fickle and mischievous nature to him.
Later, when Ash described an unfamiliar Pokémon that he but no one else had witnessed, Lillie deduced that he saw Tapu Koko, the island's guardian deity. She quickly demonstrated her fear of Pokémon when she cowered behind Ash upon being approached by one of the Tauros, only to be startled by his Pikachu.
Lillie debuted in Aloha to New Adventure!, where she tried in vain to warn Ash away from being trampled by her classmates' Tauros as he stumbled upon the school.