Logic's a wonderful thing; by logical analysis, one can determine the necessary reason for the existence of a dead city of a very high order on an utterly useless planet. Obviously a shipping transfer point! Necessarily...
It was, as usual, a decision on which the question of peace or atomic war depended. The Council of the Western Defense Alliance, as usual, had made the decision. And, as usual, the WDA Coordinator had to tell the Com Ambassador that the Coms had won again. The WDA would not risk atomic war over a minor boundary. Some hundreds of light-years away, the Survey ship Lotus floated in space over the third planet of the system, a planet exactly like Earth, only there was absolutely NO life on it.
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!