This inexplicable threat traces back to a terrifying century-old secret buried beneath the National Mall: a cache of bones preserved in amber that was hidden by a cabal of scientists—led by Alexander Graham Bell—to protect humankind. The object also holds an astonishing promise for the future: the very secret of life after death.

Now an ancient horror—dormant in the marrow of those preserved bones—is free once more, nursed and developed into a weapon of incalculable strength and malignancy, ready to wreak havoc on an unsuspecting world. Commander Grayson Pierce will be forced to make an impossible choice. To eradicate this extinction-level threat and expose those involved, he will have to join forces with Sigma’s greatest enemy—the newly resurrected Guild—even if it means sacrificing one of his own.