Vietnam War, 1966. Australia and New Zealand send troops to support the United States and South Vietnamese in their fight against the communist North. Soldiers are very young men, recruits and volunteers who have never been involved in a combat. On August 18th, members of Delta Company will face the true horror of a ruthless battle among the trees of a rubber plantation called Long Tân. They are barely a hundred. The enemy is a human wave ready to destroy them.

Thomas is turning 16. His dad's in the army and they've just moved to a town in New South Wales; his mom is pregnant; his older brother, Charlie, who's autistic, has his own adolescent sexual issues. Thomas finds Charlie an embarrassment in public, so when Thomas is attracted to Jackie, a girl in his swim class, Charlie presents any number of obstacles when she drops by their house, when the three of them go for a walk, and during a family birthday dinner. Can Thomas find a way to enter the world of teen romance and still be his brother's keeper, or is Charlie's disability going to prove more than Thomas can handle?