The Einstein Nexus: Book 3
A Novella
At first, it seemed to work.
The ever-expanding area of shifting time cleared.
But it came back, expanding faster and faster, threatening to engulf the world.
Only if the unthinkable was attempted would humanity have a chance at a future.
The Einstein Nexus: Book 3 is the third and final novella about time travel and teenage boys in the Ancient Earths series.
See the author's website for more.
Hard Science Fiction - Old School.