With a shout of "Rockets a-a-away!" three young Earthmen send the untested XL-35 rocket ship screaming into space toward the lost planet of Poseida. Space doctor Bill Hudson and two friends have courageously taken off on a forbidden flight in their eagerness to help prevent a catastrophic war between Earth and Poseida. On an earlier visit to the lost planet to do medical research, Dr. Hudson had learned to respect the intelligent but octopus-like Poseidans and had developed a lasting friendship with Kutt, the Leader's son. When the bond of good will between the two worlds reaches the breaking point, Bill devises a startling plan to outwit the small group of unscrupulous men from both planets who are behind the monstrous scheme to wreck peaceful relations. In carrying out his counterplot aided by Lt. Eddie Watkins and Courier Griff Hughes of Planet Earth Forces, Bill rights the universe in a truly dramatic manner. Here is a tale full of intrigue, suspense and deeds of daring spacemen. It explores the realms of medicine and science in outer space and reveals some fascinating probabilities. More than this, however, the story conveys to the reader an underlying theme intended to promote wisdom, fellowship and friendship among worlds and their peoples.