Off the coast of Brazil, a team of scientists discovers a horror like no other, an island where all life has been eradicated, consumed, and possessed by a species beyond imagination. Before they can report their discovery, a mysterious agency attacks the group, killing them all, save one: an entomologist, an expert on venomous creatures, Professor Ken Matsui from Cornell University.
Strangest of all, this inexplicable threat traces back to a terrifying secret buried a century ago beneath the National Mall: a cache of bones preserved in amber. The artifact was hidden away by a cabal of scientists—led by Alexander Graham Bell—to protect humankind. But they dared not destroy it, for the object also holds an astonishing promise for the future: the very secret of life after death.
Yet nothing stays buried forever. 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.
To stop its spread, Commander Grayson Pierce of Sigma Force must survive a direct attack on the island of Maui. To be there first has always been the core mission of Sigma Force, a covert team forged to be America’s front line against emerging threats. But this time, even Sigma may not be able to decipher the deadly mystery, one that traces back to the founding of the Smithsonian Institution.
With each new discovery, the menace they hunt is changing, growing, spreading—adapting and surviving every attempt to stop it from reconquering a world it once ruled. And each transformation makes it stronger . . . and smarter.
Running out of time and options, 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 it if means sacrificing one of his own.
最奇怪的是，這令人費解的威脅竟能追溯至一世紀以前，國家廣場下埋藏的驚人秘密，那是一批保存在琥珀中的骨骸。由亞力山德．格拉罕．貝爾密謀組成的一群科學家，將這項工藝品埋藏起來，為的是要保護人類。而他們之所以不敢將它銷毀，是因為這東西同時握有驚人的未來希望，也就是來世的秘密。
然而，世上沒有什麼事情能永遠埋藏。原本沉眠於那批骨骸之中的古老威脅再次獲得釋放，經過培育發展成充滿龐大邪惡力量的武器，準備摧毀毫無戒備的世界。
要阻止古老威脅擴大，西格瑪中隊指揮官葛雷森．皮爾斯必須在茂宜島上的直接攻擊中存活下來。作為美國對抗新興威脅的秘密先鋒部隊，率先抵達現場一直是西格瑪中隊的核心任務。但這次，面對這個跟當初史密森尼學會的發現有關的致命謎團，即便是西格瑪也可能無法破解。
每項新的發現都讓中隊追捕的威脅不斷改變、成長、擴大，在每次中隊試圖阻止它再次征服這個它曾經統治過的世界時，這古老威脅便不斷適應並存活下來。而每一次的轉變都讓它不只更強大，還更聰明。