Leah Lockhart is proudly science-minded and woo-woo averse. But the life she's carefully curated is knocked suddenly off course, first by a destabilizing case of vertigo, and then by an astrology reading that claims she's living way out of line with what was written in her stars.

Incensed, Leah sets off on a mission to prove that all of astrology is bogus by finding her star twins in the world--people born with her exact same astrology. But her true guides on a whirlwind journey through Venice, Istanbul, New Orleans and beyond turn out to be three people already in her orbit: the mother she thinks abandoned her, the father she thinks saved her, and the former boy next door whose love could be the path to her truest self.