if you ever happen to be in the area, look for the boys with the drums. and ask him if he remembers the girl with the violin. and ask him (if he remembers), if he remembers anything particular about her. and watch his face scrunch up as he can't remember why there would be anything special about her.
then look for the girl with the violin and ask if she remembers the boy with the drums. and watch her face grow pale as she remembers the boy with the drums.