One Day You'll Go — Sheila Schwartz

Kathy
knew, with a certainty from deep within, that
one day she would find Chris gone…Chris just
appears that summer, a dirty hitchhiker with no
place to go, and Kathy's family takes him
in. During the golden days that follow,
Kathy learns what love is. She and Chris take
long walks in the evenings, share secrets,
and always know what the other is thinking.
But Chris is a drifter and Kathy's afraid
he'll leave as unexpectedly as he arrived.
Then comes the disaster that changes
Kathy and Chris forever.