Annie is a no-nonsense Pennsylvania teacher whose hunt for a home and family of her own inspires a commitment to the abolition movement. Sylvanus, the baby brother she helped raise, is an adventure-seeking physician who finds purpose on his way to Western Africa in support of the controversial colonization effort which seeks to establish a safe-haven for former US slaves in the colony of Liberia.

In the decades leading up to the American Civil War, the siblings find themselves on opposite sides of a monumental political argument as wide and complex as the ocean that separates them. Each must question what it means to fight for freedom and determine whether political and moral convictions are enough to sever the strongest of family bonds.