Refraintale is not as much an alternate universe as it is a parallel event. It goes around the story of Ella, a girl with a gray soul,
living during the war. There is a scientist who studies the nature of souls, and she takes unwanted children as their test subjects. Ella is one of these.
All the children there were bred to have white, blank souls, but for unknown reasons Ella's was gray.
She discovers that whenever she listens to music or sings, the black particles of her soul gather to form a music note.
She knows she can't stay with such an abnormal soul, so she runs away and meets Chara, who was also running away, but from what she was running was unknown.
Ella found that Chara could not seem to remember anything, and seeing blood on a nearby stone fountain she shockingly concluded that Chara had given herself animesa.
They become close friends, and one day they visit Mt. Ebbot. When they see a hole, Chara immediately jumps. Shot with grief, Ella jumps too.
Chara's story goes on same as normal, but Ella misses the bed of golden of flowers and dies.
Her spirit lives on in Chara, and then in Chara who was also in Frisk, and she can only make her thoughts clear one way: music. This girl is the soundtrack.