When Wyman Ford is called in to investigate the mysterious exit hole of a meteorite that amazingly passed straight through the earth, what he finds defies all we know about our universe.
With Khmer Rouge interest in a gem mine on the Thai Cambodia border, a shipwreck off the coast of Maine and evidence of a possible cover-up at NASA headquarters, Ford realises he's uncovered something much bigger than even he anticipated.
With the help of amateur scientist, Abbey Straw, he discovers the existence of an ancient structure buried deep in Voltaire Crater on Deimos, one of Mars moons. Sticking up from the structure is the unmistakable outline of a gun. It seems it was built to monitor the solar system, and destroy any intelligent life powerful enough to challenge it – but by whom?
A quick calculation of the orbit of Mars indicates that Deimos Crater will once again point at earth in sixty hours. The final shot will come then. Can the team figure out a way to stop this weapon before it destroys the world as they know it?
Sixty hours and counting...