On Fitzroy Foster's fourteenth birthday on September 11, 1981, he receives an unexpected and unwelcome gift: when his father snaps his picture with a Polaroid, another person's image appears in the photo. Fitzroy and his childhood sweetheart, Cam, set out on a decade-long journey in search of this stranger's identity - and to reinstate his own - across seas and continents, into the far past and the evil and good that glint in the eyes of the elusive visitor.