Increasingly wary of her father’s genetic research, Rachel Kramer has determined that this trip with him to Germany --- in the summer of 1939 --- will be her last. But a cryptic letter from her estranged friend, begging Rachel for help, changes everything. Now hunted by the SS, Rachel turns to Jason Young --- a driven, disarming American journalist and unlikely ally --- who connects her to the resistance and challenges every ideal she once had.