Sue had delayed going through her mom's stuff after her death. Just going into her mom's room made her depressed. She wasn't surprised to find that her mom had kept her dad's letters, but it was many months after her mom's death that she found them.
Sue found more than just her dad's letters tucked away in the bundle of papers, though, and the other note she found didn't make any sense to her at all. She determined that it must have confused her mom also. Otherwise, surely, her mom would have told her about it years ago.
Sue had never known her dad, Joe de Cou, because he had been declared Missing in Action just after she was born. But subsequent odd events suggested he might not have died. Decades later, she was determined to find out--to go on a quest for her own peace of mind. She just wanted to know for sure what had happened to him.