Melbourne high school student Tom finds himself thrown into a world of adventure and intrigue as he escapes to the Snowy Mountains with illegal Irish immigrant, Sean. The pair settle on a friend's farm at Dalgety near the Snowy River and begin a journey of recovery from their pasts. Tom meets Cassandra who is passionate about the health of the Snowy River and the mountains. Together they break in the wild brumby Brindabella and Tom rides his horse to fame at the local bush races. When Cassandra becomes the target of a deeper plot to privatise Australia's water, Tom springs into action to find the assassin. The main characters bond through their shared passion for the mountains and loyalty to one another.
