Following the death of her mother, a young woman returns after many years to the weather-beaten family home on the shores of Sydney's Botany Bay. But the old family home begins to bring old wounds more and more to life. The story unfolds through flashbacks yet as it progresses the flashbacks merge into the present as it becomes apparent that the situation Tessa has returned to is very much the result of that which passed before.

Loosely based on the filmmaker's personal experience, "Terra Nullius" is an impressionistic account of an eight year old Koori girl, Alice, growing up in a white adoptive family which denies her Aboriginality. The film examines how unacknowledged shame and fear passes from one generation to the next, from one culture to another. The last scene depicts a silent meeting between the young Alice and the adult Alice. In order to reclaim her life, Alice decides she must confront the pain and confusion of her childhood.

Mona and her adult daughter, Kymmy, set out from their country home to get Kymmy's young son from foster care in the city. As they travel they face and overcome many setbacks, and their past and future are explored. They argue and part ways. Kymmy gets to the foster home only to find another obstacle in her way. Mona arrives later and brings about a surprising and provocative resolution.