West Berlin, 1979. Helen Abell oversees the CIA's network of safe houses, rare havens amidst the dangerous milieu of a city in the grips of the Cold War. Helen's world is upended when she overhears a meeting between two people speaking a coded language that hints at shadowy realities far beyond her comprehension. Before the day is out, she witnesses a second unauthorized encounter. Her attempts to expose the dark truths about what she has witnessed will bring about repercussions that reach across decades and continents into the present day, when, in Maryland, a young man is arrested for the double murder of his parents, and his sister takes it upon herself to find out why he did it.