After the player defeats Kahuna Hala, she goes to Akala Island alongside the player and Hau. After the player completes their first trial, Nebby escapes from her bag and runs off into Melemele Meadow, so the player must find it and return it back to her. After assisting the player at the Trainers' School, she visits Hau'oli City. Sometime after that, she accompanies the player to Kukui's Lab and later provides them a tour of the Pokémon Center. Afterwards, she accompanies the player back to Iki Town, where she watches them receive their starter, and later their Z-Ring or Z-Power Ring. Despite not yet having a Pokémon of their own, the player steps in to protect Nebby, and is in turn assisted and recognized by Tapu Koko. The player first meets Lillie on the Mahalo Trail, where she watches helplessly as Nebby is being attacked by a group of wild Spearow on an unstable rope bridge.

She contacts her husband, Professor Kukui, who allows her to stay with him as his assistant. Lillie and Nebby wash up on a beach, where they are found by Professor Burnet, who listens to Lillie's story and agrees to help her learn more about Nebby. Just when she is surrounded, she is Teleported by a mysterious force, later revealed to be the Pokémon hiding in her bag, Cosmog, which she nicknamed Nebby. Lillie is first seen attempting to flee Aether Paradise three months prior to the beginning of the player's adventure, during the opening cutscene. She dislikes Pokémon battles as she does not like seeing Pokémon get hurt but loves to read.

She assists, and is shown to live with, Professor Kukui for personal reasons. Lillie is first revealed as a mysterious girl who is central to the plot of Pokémon Sun and Moon.

Hapu and lillie