Tracing the lead-up to and aftermath of a bloody showdown when the superintendent of a Queensland mission goes on a murderous rampage.

In 1930 the superintendent of a mission on a Queensland island, driven mad by his wife's death, goes on a murderous rampage. Fearing for their lives, the other whites arm a young Indigenous man and order him to shoot Uncle Boss dead. The Multiple Effects of Rainshadow traces the lead-up to this bloody showdown and the repercussions in the years after - for Aboriginal people and the colonial overseers.