A remote military research station sends out a frantic distress call, ending with a chilling final command: Kill us all! Personnel from the neighboring base rush in to discover everyone already dead - and not just the scientists, but every living thing for 50 square miles is annihilated: every animal, plant, and insect, even bacteria. The land is entirely sterile - and the blight is spreading. To halt the inevitable, Commander Gray Pierce and Sigma must unravel a threat that rises out of the distant past.

Galilee, 1025. A cunning Templar knight uncovers a holy treasure: the Bachal Isu - the staff of Jesus Christ - a priceless icon that holds a mysterious and terrifying power that will forever change humanity if unleashed. A millennium later, Somali pirates hijack a yacht off the coast off the Horn of Africa, kidnapping a young pregnant American woman and brutally killing her husband. Painter Crowe and his SIGMA team are enlisted for the top secret rescue mission. The kidnappee is the daughter of the U.S. President.

A series of strange events throws the world into turmoil. As a manned Chinese rocket explodes upon launch, three American astronauts, each separated by thousands of miles, are murdered. Then an archaeologist in Croatia uncovers a new cavern system that reveals elaborate primitive paintings by a tribe of Neanderthals.

Deep in the Rocky Mountains, a gruesome discovery - hundreds of mummified bodies - stirs international attention and fervent controversy. Despite doubts to the bodies' origins, the local Native American Heritage Commission lays claim to the prehistoric remains, along with the strange artifacts found in the same cavern: gold plates inscribed with an unfathomable script.

At Princeton University, a famed geneticist dies inside a biohazard lab. In Rome, a Vatican archaeologist is found dead in St. Peter's Basilica. In Africa, a U.S. senator's son is slain outside a Red Cross camp. The three murders on three continents bear a horrifying connection: all the victims are marked by a Druidic pagan cross burned into their flesh. The bizarre murders thrust Commander Gray Pierce and Sigma Force into a race against time to solve a riddle going back centuries.

In Washington, D.C., a homeless man dies in Commander Gray Pierce's arms, shot by an assassin's bullet. But the death leaves behind a greater mystery: a bloody coin found clutched in the dead man's hand, an ancient relic that can be traced back to the Greek Oracle of Delphi.

A construction project beneath the National Mall reveals a dark secret dating back to the Civil War, something buried by a cabal of scientists, led by Alexander Graham Bell, who helped found the Smithsonian Institution. It is a cache of bones, preserved in amber, protecting a wonder like no other, the very secret of life after death. But such a prize is guarded by a horror out of the ancient past, a horror that still lives in the marrow of those bones - and is now free again.

Arriving home on Christmas Eve, Commander Gray Pierce discovers his house ransacked, his pregnant lover missing, and his best friend’s wife, Kat, unconscious on the kitchen floor. With no shred of evidence to follow, his one hope to find the woman he loves and his unborn child is Kat, the only witness to what happened. But the injured woman is in a semicomatose state and cannot speak - until a brilliant neurologist offers a radical approach to “unlock” her mind long enough to ask a few questions. 

From the depths of the Indian Ocean, a horrific plague has arisen to devastate humankind - a disease that's unknown, unstoppable, and deadly. But it is merely a harbinger of the doom that is to follow. Aboard a cruise liner transformed into a makeshift hospital, Dr. Lisa Cummings and Monk Kokkalis, operatives of SIGMA Force, search for answers to the bizarre affliction. But there are others with far less altruistic intentions.

High in Nepal, a monastery erupts with savagery and madness. Deep in a German mine, abomination wears the innocent face of a child. Hidden in the jungles of Africa, experiments rooted in a dark past have found fertile ground again.

During a crowded service at a cathedral in Germany, armed intruders in monks' robes unleash a nightmare of blood and destruction. But the killers have not come for gold; they seek a more valuable prize: the bones of the Magi who once paid homage to a newborn savior...a treasure that could reshape the world.

An inexplicable explosion rocks the antiquities collection of a London museum and the race begins to determine how it happened, why it happened, and what it means. Lady Kara Kensington's family paid a high price in money and blood to found the gallery that now lies in ruins. Her search for answers leads Kara and her friend Safia al-Maaz, the gallery's curator, into a world they never dreamed existed.

Will Robie is an assassin with a mission. But whose side is he on?

Back in DC after successful missions in Edinburgh and Tangier, assassin Will Robie sees his latest assignment, to eliminate a US government employee, go badly wrong. What had she done? Or what did she know? Robie is now a wanted man. But it seems that he’s not the only one on the run. Young teenager Julie Getty is devastated by the inexplicable murder of her parents. Robie and Julie meet when he saves her from an attempt on her life as they are trying to leave town....

Off the blustery streets in the medieval heart of Budapest, Captain Tucker Wayne and his war dog, Kane, rescue a mysterious woman fleeing three armed men. The secret she holds will unlock a terrible treasure, one steeped in blood and treachery, tied to a crime going back to the fall of Nazi Germany and a heritage of suffering and pain that reaches out from the past to wreak havoc today.

On a transatlantic flight, the two black sheep of Sigma Force - Seichan and Kowalski - must set aside their mutual dislike as a mysterious fiery force knocks their aircraft out of the sky. This unlikely duo must use every skill, weapon, and bit of ingenuity to survive a night on a remote volcanic island, where their only refuge is the haunted, bat-plagued grounds of a seemingly deserted resort. But something horrific awaits the two, something born of the latest science but rooted in our basest human instincts.