Adelaide, 1916, and Dora Somerville grieves for her brother, Edgar, killed in France. In the course of an oppressively hot summer, she decides to abandon her pacifist beliefs and embrace violence as a means to end the Great War.
In his printing shop, her lover, Daniel Bone, also makes a momentous decision. He can no longer face the constant pressure to fight in the war – he will join an Antarctic expedition and abandon Australia, leaving Dora behind. However, the peace Daniel seeks eludes him when he is caught up in a crisis in the icy wilderness as the men find themselves under attack.
When the lovers parted, they had agreed to write to one another, although they knew the letters would never be sent. Thousands of miles apart, their passion grows as the decisions they have made imperil them both.