My Version
The boy was the only true love of the girl, when he died she get in deppresion, the boy after seeing how his love is, he come back like a spirit and tried to help the girl by bringing the things hat wereas special to her, when he get his possesions the girl is happy again learning that she needs to go on. the world is not grey anymore,and when the boy complete hes task he can finally rest in peace, then the girls let him go (the white piegon)