From Astounding Stories of 1932. Earth is being attacked by horrible black monsters that appear from nowhere and destroy and kill everything and everyone in their paths. Nothing affects them, nothing stops them; they are impervious to all weapons. Earth is doomed. But there is one hope and it rests on the shoulders of 98 brave men. Can they do it? can they find a way of retaliating? Listen and find out.

Clifford Simak deals with the implications of time travel in his own unique way in this story. What if a group of guys did it on their own, without any help from government or industry? On a shoestring,so to speak? Would anyone believe them? What would you do if you could go back 150,000 years to a time when mastodons and saber toothed tigers roamed North America? And what happens when they run out of money? All these questions are explored in the usual humorous, wry Simak way in this story.