From the #1 New York Times bestselling master of international intrigue comes an all-new Sigma Force adventure introducing a dynamic younger generation of operatives, replete with all the world-challenging threat and scientific mystery that are the hallmarks of this bestselling series.

Simon Reese, CEO of Voyager X, built his luxury travel empire on one promise: take the ultra-wealthy somewhere no one has ever been. His latest venture is the most ambitious yet—a journey deep into the mountainous cloud forests of Peru, where a sprawling set of ancient ruins sits untouched. The goal: to trace the origins of humankind itself.

Billionaire Gordon Messick is the perfect client. Charismatic, fearless, and eager for the ultimate adventure, he signs on immediately, bringing his wife and two young children along for the ride.

An advance survey team is sent to scout the ruins ahead of the Messicks’ arrival. When they vanish, Simon assumes they’ve been grabbed by local guerrillas who plague the region. Until one of the missing men reappears, his body ravaged by vines and roots growing from his flesh.

Simon buries the story. He’s invested too much, risked everything for this venture.

Accompanying the Messick family, security chief Erin Rand and naturalist Sam Hess have their own shared—and secret—agenda. Dispatched by Sigma Force, the covert field arm of DARPA, they’ve been sent to find out what really happened to the advance team.

For something is deeply wrong with these ruins. And as the danger grows, it becomes evident that the forest holds a greater secret, one going back to humanity’s origins and an inexplicable biological mystery.

When Gordon Messick’s young son disappears into the mist, Erin and Sam realize they aren’t just racing to contain a threat—now they’re fighting to bring a child home alive before the jungle makes sure none of them leaves at all.

Some things are best left lost forever.