As Selene and Lillie approach the Altar of the Moone, Lillie is plagued by self-doubt, recalling Lusamine and her dismissive question of how she plans to save Nebby. Lillie remembers moments of her journey in Alola, like the time her fear held her back from saving Nebby from a Spearow flock at Mahalo Trail, her confrontation with her mother in Aether Paradise, and witnessing Lusamine using up Nebby's power to force open an Ultra Wormhole to locate and defeat Necrozma. With Selene's guidance, Lillie reaches the top of the altar, and together with Selene, plays the Sun and Moon Flutes to activate the altar. A bright pulse of light erupts from the altar's central platform, prompting Nebby to fly into the light, evolving into Lunala as the light fades.
Lillie shares a tender moment with Lunala, pleading with Nebby to take her to where Lusamine is, declaring that she doesn't have to take on Necrozma all by herself. Before Lunala can respond, an Ultra Wormhole opens up above the altar, dropping Lusamine and Guzma to the ground, severely beaten and injured. Lillie runs over to her mother, and a clearly shaken Lusamine begs for the children to run away, describing Necrozma as a monster that attacked as soon as it was approached. Necrozma tears its way out of the wormhole, and after exchanging a look with Lillie, Nebby soars forth to do battle, exchanging series of devastating attacks with the Prism Pokémon.
Ultimately, after Nebby gets pinned by Necrozma, the latter absorbs Nebby into its body, changing into its Dawn Wings form. With all hope lost, Lillie appears about to collapse from fear, before noticing Selene brandishing a Poké Ball, ready to battle the new threat. The sight is enough to reaffirm Lillie's convictions as she stands up again, looking at Necrozma with a determined expression.