When Cameron was fifteen, Sonia was her best friend--no one could come between them. Now Cameron is a twenty-nine-year-old research assistant with no meaningful ties to anyone except her aging boss, noted historian Oliver Doucet.

When an unexpected letter arrives from Sonia ten years after the incident that ended their friendship, Cameron doesn't reply, despite Oliver's urging. But then he passes away, and Cameron discovers that he has left her with one final task: to track down Sonia and hand-deliver a mysterious package to her. Now without a job, a home, and a purpose, Cameron decides to honor his request, setting off on the road to find this stranger who was once her inseparable other half.