Paddy (Robert Mitchum) is an itinerant farm worker, travelling the Australian outback. His wife, Ida (Deborah Kerr) and son, Sean (Michael Anderson) want to settle down and have a permanent home. Paddy hates predictability and routine, and wants to keep the freedom to move off on a whim. The three of them take jobs at a sheep shearing plant, to save money for their own farm. As they get close to having enough money, Paddy wants to quit. They save the money they need, and go back to the farm Ida wants. Paddy disappears in the night. The next day he returns, and he has gambled away all the money.
Paddy wins a race horse gambling. Sean wins a few local races riding it. A man wants to buy the horse, and offers enough money for them to buy the farm. Paddy refuses. The movie ends with them hitting the road again in their little horse drawn caravan, to look for farm work.
Note: The name of the movie comes from an Australian word which refers to someone with no fixed home, who lays their head down to sleep wherever they happen to be when the sun goes down.
Thanks Joseph C!