A measurement that should be impossible. A discovery someone has spent decades keeping buried.Experimental physicist Adam Corbett distrusts elegant surprises. When an atom interferometer produces a residual that reverses on command, he assumes the instrument is wrong.The tests hold.A forgotten experiment points to the same impossible result. Records begin disappearing. Oversight tightens. Then Adam's older brother dies, leaving evidence that the discovery has been managed-and buried-for decades.As Adam's investigation draws his family, friends, and scientific team into danger, trust begins to fracture. Some want the truth exposed. Others believe it must be controlled. And the people closest to him may know more than they have admitted.To prove the effect is real, Adam must move the experiment beyond the laboratory and into reduced gravity. But the closer he gets to an independent answer, the more dangerous the line becomes between protecting the world from a discovery and controlling who is allowed to make it.The Unseen Constant is a grounded science thriller about an impossible result, a hidden institutional history, and the cost of asking a question powerful people have already decided should remain unanswered. It is Book One of the Beyond the Boundary Series.