The scene in which Cleo is rehearsing a new song that is brought to her by two young males who write the music for her, is extremely moving and heart wrenching. You can see the overwhelming emotions in Cleo when she is singing the song about love, and death. After seeing Cleo sing into tears you realize that she realizes she's going to die.
The way in which they follow her around doing everyday tasks, but showing the thoughtfulness in every action she does, and the observant manner in which she sees every fine detail that surrounds her. She's so caught up in the idea of no one caring if she lives or dies, and plays her own song to see if anyone notices or cares, and they don't. Or at least thats how she sees people not caring if she lives or dies.
Finally she meets someone who grounds her thoughts of death, and gives her a reason not to fear death but to embrace life. This man faces death also, but in a different way by going off to war. The end we see her doctor who tells her that she does have cancer and that she'll get chemo and things will be okay. As if the build up of whether she has it was bigger than actually having it and dealing with it.