Inspired by the events surrounding the bombing of Japan in 1945, 'Boomerang' is one of the earliest stories to warn of the danger of accidental nuclear war. Set in the aftermath of the destruction of most of the inhabited areas of the world, the events are recalled by an old man sitting with his grandson at Sydney's Circular Quay. Nearby are the remains of what used to be the Sydney Harbour Bridge.
The old man recalls the international race to be the first country to put a manned space craft on the moon, a race that started soon after the end of World War II and eventually escalated to involve individual cities around the globe - the Australian competitors being Sydney, Melbourne, Adelaide, Perth and Hobart. Hostilities soon broke out on the moon between old enemies but it was only when the rockets begin to fall on Earth that the world became aware that most are armed. "But wot did 'appen' Granddad?' asks the boy. Picking up his grandson's toy boomerang the old man throws it in the direction of the moon. "Can't yer see? They loaded all them rockets up wi' uranium - an' sent 'em back!' (p.129).