Sigma Force Books in Order

A Vatican archivist is executed in Moscow, but not before he sends a coded warning to Gray Pierce. Sigma Force races to find a legendary hidden library and the map to Hyperborea—before its discovery sparks disaster.

An international research station in the Coral Sea comes under attack during a cascading geological disaster—quakes, tsunamis, and eruptions. Sigma Force must uncover what’s been buried deep in the planet before the crisis goes global.

Villagers in the Congo are found in a catatonic state while the surrounding wilderness grows smarter and more lethal. Sigma Force investigates a force that could accelerate evolution—and spread far beyond the jungle.

An archaeologist’s death kicks off a globe-spanning hunt for answers hidden in ancient myths. Gray Pierce and Sigma Force race through ruins and modern danger to stop a discovery that could rewrite human history.

A brutal crime scene uncovers a link between old secrets and modern science, sending Sigma Force into a race across borders. With a new weapon in play, Gray Pierce must solve the puzzle before a hidden project triggers catastrophe.

A violent attack and a strange biological threat pull Sigma Force into a case that spans oceans and islands. As engineered organisms and environmental chaos collide, Gray Pierce realizes an ancient catastrophe may not be finished with us.

A burned body on an isolated Australian beach drags Gray Pierce and Seichan into a centuries-old mystery. The trail leads to a vanished convict ship, where mutiny, treasure, and modern betrayal collide.

A boy is found wandering near an ancient tomb carrying an infection that looks like a biblical plague. Sigma Force races from Egypt to laboratories worldwide, trying to stop an outbreak before it becomes unstoppable.

Tucker Wayne and his military working dog, Kane, are drawn into a rescue that turns into a manhunt. In hostile terrain and with a ruthless opponent closing in, the pair must rely on training, loyalty, and raw endurance to survive.

A Sigma Force short story that flashes back to a tense solo operation. With limited support and a mystery that won’t stay buried, the agent at the center must decide who to trust before the night ends in disaster.

In Croatia, an archaeologist uncovers a hidden chapel containing bones that don’t fit human history. Sigma Force follows the trail into questions about our origins, and an enemy willing to kill to keep those answers buried.

On an Amazon river cruise, Cotton Malone teams up with Sigma Force commander Gray Pierce to stop a rogue botanist. Their target wants to sell a rare orchid that produces a deadly neurotoxin, and the buyers aren’t worried about mass casualties.

A mystery tied to vanished species sends Sigma Force from ancient sites to modern laboratories. As the team uncovers what drove previous mass extinctions, they realize the next one could be engineered—and humanity is the target.

A clue hidden in the past points Sigma Force toward the long-lost tomb of Genghis Khan. Gray Pierce partners with Vatican experts as nations race for a weapon that could end wars—or end the world.

Former Army Ranger Tucker Wayne and his military working dog, Kane, take on a mission that tests their bond and their instincts. What begins as a search turns into a pursuit with lives on the line and no room for mistakes.

A shocking discovery in an ancient tomb hints at a hidden chapter of human history. At the same time, a woman abducted off Africa’s coast becomes a living clue, pulling Sigma Force into a race between rival powers.

A Sigma Force short story sparked by an ordinary-looking key that unlocks a dangerous secret. As hidden files and forgotten doors open, a small clue becomes a lethal target—and stopping the leak matters more than survival.

A cave discovery in the Rocky Mountains uncovers mummified bodies that shouldn’t exist, igniting a battle over who controls the site. Sigma Force is sent in, only to find the find is linked to a larger, deadlier plot.

A baffling murder investigation leads Sigma Force toward an ancient secret tied to disease and power. Gray Pierce follows cryptic symbols across Europe, trying to stop a discovery that could unleash a modern doomsday.

When children with rare genetic traits become targets, Sigma Force starts asking questions no one wants answered. Gray Pierce follows the trail from secret labs to ancient sites, where a long-buried mystery meets cutting-edge science.

A hijacked cruise ship and a deadly pathogen put Sigma Force on the clock. As the contagion spreads, Gray Pierce must untangle ancient clues and modern bio-terror before the outbreak turns the world’s ports into mass graves.

A Sigma Force short story that drops Kowalski into an off-the-books mystery far from headquarters. What starts as a personal detour turns dangerous fast, and his instincts may be the only thing keeping people alive.

When monks in the Himalayas suddenly turn violent, Sigma Force suspects something engineered. Gray Pierce and his team trace the outbreak across continents, uncovering a plan that uses biology—and belief—as leverage.

A theft linked to the relics of the Three Wise Men pulls Sigma Force into a deadly race. Gray Pierce follows a trail of assassins and secret societies, knowing the prize could be turned into a weapon.

An explosion at a London museum draws Sigma Force into its first mission. Commander Gray Pierce chases clues from the crime scene to remote deserts, where a hidden technology threatens to reshape the modern world.