The Terran system is growing and expanding all the time. But an old and corrupt Centaurian Empire is holding Terra down, as it encircles the Terran system and will not let the humans grow out of their current empire. For this reason Terra is at war with Proxima Centauri and is trying to find a way of breaking free from the Centaurian's hold upon them.
In the war that results, Terra is continually coming up with new weapons to try and break the Centaurian defenses, but Proxima Centauri is also continually updating its defenses
This is where Thomas Cole, known as The Variable Man, comes in. Cole is a man from the past, from 1913, the time just before the First World War. He is brought into the present (or future depending on perspective) as an accident via a Time Bubble that was used for research about the past. It is discovered that this man has a certain genius to fix things and make things work. This is because he comes out of a period of time when humans had a natural genius and an ability to invent things and to solve problems. It is at this point that the man working on the FTL (Faster Than Light) bomb realizes that The Variable Man is the only person who can make it work.