LATE on the evening of May 28, 1993, something shattered the calm of the Australian outback and radiated shock waves outward across hundreds of miles of scrub and desert. Around the same time, truck drivers crossing the region and gold prospectors camping nearby saw the dark sky illuminated by bright flashes, and they and other people heard the distant rumble of loud explosions.

The mysterious event might have been lost to history except for the interest of Government investigators in Australia and the United States who eventually came to wonder if the upheaval was the work of the Japanese doomsday cult accused of the poison-gas attack on Tokyo subways in 1995 that killed 12 people and hurt thousands.

The fear was that the terrorists had acquired nuclear arms or other weapons of mass destruction and had been testing them that night in the Australian wilds.

The hope was that the upheaval was an earthquake, a mining explosion or even a meteorite strike from space, any natural event.