Why did everybody step off the ship in this strange valley and promptly drop dead? How could a well-equipped corps of tough spacemen become a field of rotting skeletons in this quiet world of peace and contentment? It was a mystery Peter and Sherri had to solve. If they could live long enough! Peter Wayne took the letter out of the machine, broke the seal, and examined it curiously. It was an official communication from the Interstellar Exploration Service. It read: FROM: Lieutenant General Mart