-Last photography of the sibblings together-

BThe Evans sibblings: Scott Evans, 17 years old and Anna Evans, 15 years old. They were like a soul divided in two, those who did not know them would think they were couple, those who did know them could not belive they could get along so well. They lived alone, their parents work overseas so they were at home and were so bussy they could not call then too often. Even so the sibblings were happy....they were...until a trafic accident took Anna's life.
The happy and lively Scott everyone at school loved also died with Anna, he became a totally different person, silent as a tomb, cold to everyone and lonely.

This is where your chatacter appears, we can discuss whether she had already fallen in love with Scott from the beggining or simply did it to help. In any case a girl from another class walks in front of his table, she looks just like Anna but with shorter hair, this took Scott by surprise, then she said something that surprised him even more
"I will be your sister from now on"