In the spring of 1974, Calliope Stephanides, a student at a girls' school in Grosse Pointe, Michigan, finds herself drawn to a chain-smoking strawberry blond classmate with a gift for acting. The passion that furtively develops between them - along with Callie's failure to develop - leads Callie to suspect that she is not like other girls. In fact, she is not really a girl at all. The explanation for this shocking state of affairs is a rare genetic mutation - and a guilty secret - that have followed Callie's grandparents from the crumbling Ottomon Empire to Prohibition-era Detroit and beyond, outlasting the glory days of the Motor City, the race riots of 1967, and the family's second migration, into the foreign country known as suburbia. Thanks to the gene, Callie is part girl, part boy. And even though the gene's epic travels have ended, her own odyssey has only begun.