A battle is raging in Café Sonata between a wild Vullaby and White's Pokémon. Bianca starts playing some unfamiliar piece of music, promising the injured guitarist that she will do her best to replicate the music the guitarist has practised many times. Bianca sees that the music is titled "Relic Song", and also hears from the guitarist how his mother inspired him to become one. Thus, Bianca begins to play the song with the guitarist's guitar.
Vullaby instantly goes for Bianca as soon as she strums a chord; Dorothy intercepts with a Electric-type attack to slow Vullaby down. White voices her encouragement to a Bianca short of confidence, and gets Nancy and Solly to occupy Vullaby as well. With enough time to sight-read, Bianca eventually builds up the melody of Relic Song, and the cowering Meloetta begins to respond to it, much to the guitarist's pleasure. Vullaby overthrows its resistance and goes for Bianca again, only for Nancy to block it. Bianca soon manages to play the Relic Song smoothly, allowing Meloetta to sing along to it.
By then, Vullaby has knocked out all of Dorothy, Nancy and Solly, and goes for Meloetta. This time, Meloetta's voice knocks Vullaby back. A stunned White realizes that Relic Song is actually a move, which the guitarist confirms, saying that Meloetta has now remembered its forgotten move. An exhausted Bianca finally finishes playing the Relic Song, and is congratulated by both White and the guitarist.
Vullaby gets back on its feet and calls an entire flock of its kind. They infiltrate the café and target Meloetta all at once. However, Meloetta knocks them back with Relic Song, then begins to transform. White wonders if the Relic Song also makes Meloetta change appearance. At the next moment, Meloetta retaliates against the flock, kicking down each Vullaby one by one using its new form. It continues to struggle against the lead Vullaby.
Bianca and White thus decide to assist Meloetta through battle. They call out Oshawott and Amanda respectively. White whispers her strategy to Bianca, then calls Amanda forward to deliver a Leaf Tornado. Although Vullaby appears to withstand the attack, it then feels something go through its rear. White explains to the guitarist that Leaf Tornado distracted Vullaby, allowing Bianca's Oshawott to send its scalchop through its diaper-like bone and hit Vullaby's weak spot.
Vullaby stumbles, and Meloetta delivers the final blow. White responds by throwing out a Poké Ball towards Vullaby to capture it. Bianca is amazed at the easy work of White's capture, and White reveals that she already has a nickname for her new catch: Barbara. Thus, Bianca calls Professor Juniper through her Xtransceiver, awakening her in the middle of the night and surprising her with the sight of Meloetta. Bianca concludes the story about how she met Meloetta, with a desire to learn more about Pokémon, and thus assist Juniper with her work, and abandon her Pokédex mission. This causes Juniper to fret, but Bianca tells her not to worry, as she will pass her Pokédex to the person next to her, who has proven a greater battling skill than her. With that, White becomes just as stunned as Juniper when she meets her face in front of the Xtransceiver camera.
The next morning, Juniper's father Cedric meets up with White and Bianca, presenting White with the Pokédex meant for Bianca, that he fixed. Bianca then waves goodbye to Meloetta as it departs, thanking the mirage for giving her a new purpose in life. White also then begins to depart. After Bianca expresses concerns about Cheren, White promises to tell Black about it, and flies away on Barbara.