TUNGUSKA, JUNE 30, 1908: The most catastrophic impact in recorded history rocks the Central Siberian plateau, flattening thousands of square kilometres of ancient forest and sending shockwaves around the globe, yet leaving behind not a shred of evidence as to what caused it.

Could the impactor have been a primordial black hole? Earth’s encounter with such a fantastic object — smaller than an atomic nucleus, more massive than a mountain, older than the stars — could account for all the phenomena of the Tunguska Event.

All, save one: An infalling micro-hole should have burrowed unhindered through the solid mantle of the earth, bursting up out of the North Atlantic hours later with as much multi-megaton force as the original impact. Absent any trace of such an exit event, the black-hole hypothesis was swiftly consigned to the dustheap of astrophysical history.

And yet …

110 years after Tunguska, maverick cosmologist Jack Adler is researching a new and improved scenario: What if there was no exit event because the black hole itself never came out? What if it fell into orbit around earth’s core instead? What if it’s still down there, tunneling through the lithosphere, slowly consuming the planet?

Unfortunately, Adler’s not alone in his surmise. A renegade Russian oligarch is plotting to capture the orbiting micro-hole and expose what lurks at its heart: a naked singularity — a gravitational point-source powerful enough to warp space and time itself.

Now only a rookie government agent and the ueber-consultant she’s drafted into helping her stand in the way of a world-spanning conspiracy aiming to conquer the future by rewriting the past.

When the six-year-old daughter of billionaire technocrat Davoud Ansari is kidnapped, ueber-consultant Jonathan Knox and counterterrorism agent Marianna Bonaventure must team up with an experimental artificial intelligence to rescue her, never suspecting the little girl is key to a plot that could destroy the NSA’s most advanced cryptanalysis capability — and kill every man, woman, and child in the United States.

For Jon and Marianna Knox, the birth of their daughter Persephone marks the happiest day of their lives. Until they learn that Persey is suffering from a rare but fatal condition called "triploidy."

Her doctors are baffled, and with good reason. Because the source of the little girl’s genetic malfunction is not of this earth. It lies out beyond the orbit of Saturn.

And it’s coming for all of us.