This wasn't supposed to happen to Harry. She wasn't supposed to disappear from his life like this. Like the fairy tales go; they meet and fall in love at first sight, get married and live happily ever after.
But the stories never factored into reality. People don't fall in love at first sight, and they certainly don't always live happily ever after. Harry is no prince, and this isn't a Cinderella story.
When Harry's girlfriend Sophie disappears from his life, his story is changed forever. He just knows he won't be the same without her with him. But when Harry finds a letter from Sophie that starts an adventure into her past, it's up to him to travel back to discover what he never knew, and what she never said.