Deborah Cheetham’s Pecan Summer will receive a one-off performance at the Opera House.

When Deborah Cheetham started writing Pecan Summer, Australia’s first Indigenous opera, telling the story of the walk-off from the Cummeragunja mission, she had no idea that her own family had been involved in the protest. Cheetham is an Indigenous opera soprano, composer, director and producer from the Yorta Yorta nation. Looking for a subject for an opera, she was told about the 1939 protest by Aboriginal elders. The Cummeragunja Mission walk-off was the first mass strike by Indigenous people in which more than 200 people, most Yorta Yorta men, women and children, left the mission in protest at the appalling, inhumane conditions. Crossing the Dhungala (Murray) River, they set up camp and demanded the removal of the station’s manager.

When Cheetham began researching the protest, she discovered that her own grandparents had been involved, leaving the mission with their first son, Jimmy Little, then just two years old. Cheetham, it turns out, is the niece of Little, now an acclaimed singer/songwriter. “It was just wild. The last decade of my life has been the most incredible uncovering of things that I never knew,” she says.

“From the...