Buried beneath the National Mall lies a terrifying secret, dating back to the founding of the Smithsonian Institution: a cache of bones preserved in amber. The artefact 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, ready to wreak havoc on an unsuspecting world.To be there first has always been the core mission of Commander Grayson Pierce and Sigma Force. But this time, even Sigma may not be able to decipher the deadly mystery. With each new discovery, the menace they hunt is changing adapting and surviving every attempt to stop it from reconquering a world it once ruled.Running out of options, Gray will be forced to make an impossible choice. To eradicate this extinction-level threat, he will have to join forces with Sigma’s greatest enemy the newly resurrected Guild even it if means sacrificing one of his own.