The launching of the Firebird Rocket is endangered when a famous rocket scientist disappears without a trace on his way to the Woomera Monitoring Station in Australia. Assigned to the case, Fenton Hardy tells his sons he needs their help. And Frank and Joe must turn down a request that they find the missing son of a prominent senator. The search for the scientist begins at the Princeton Space Laboratory, where the boys realize they are being hunted by an unknown adversary. Clues lead them to Australia, and again they are followed. Then suddenly their lives are in danger! Someone in an automobile tries to run them over; and, later, at dockside, a heavy cargo bale falls and just misses them. Disregarding the danger and warnings of worse to come, the boys follow the trail to a cattle station in the Australian Outback. With courage, wit, and clever detective work, the young detectives begin to close in on the enemy, only to discover that the tables have been turned. Captured by their cunning adversaries, the Hardys face certain death! Will they escape? Will the Firebird Rocket ever be launched? Read this exciting mystery about Frank and Joe's most difficult case. - Flyleaf.