It's based on the events of 6 April 1966, where, in the Melbourne suburb of Westall, 200 students, staff and local residents watched as a strange object hovered overhead for several minutes, landed briefly, then lifted off and vanished. Witnesses described it as low flying, silver-grey and shiny, shaped like a 'cup turned upside down on a saucer' and accompanied by five light aircraft. A mass of excited students surged out of school and ran after the object. Many reported seeing a circle of flattened grass on the ground where it had landed. One said she touched it as it took off. Others observed men in uniforms cordoning off the 'landing site' and removing soil samples by the truckload. Some say they saw uniformed men torch the area a few hours later. The incident was reported on the news on television that night and in the local newspapers.