Your destiny is already mapped out as soon as you're born - you just don't get to see it yet.
In this era, people are given necklaces at birth. On these necklaces, an empty, corked bottle hangs. And as time goes by, your bottle fills with multicolored sand in a specific pattern. When you come of age, your bottle is full. Only one other person shares the same sand pattern as yourself, and that is the person you are meant to be with. Trinity Harpers, our dashing heroine, has just come of age. And her match - well, he's not exactly the Prince Charming she had in mind.
And destiny is a funny thing - it doesn't like to be messed with.