Lea, a diminutive but fierce scholar, longs to see her name among the great explorers in museums across the world. Her husband, Thomas, is a capable but somewhat oblivious academic who seeks the answers to the great mysteries left behind when the gods vanished from the land of Anthumbra in a world-changing Upheaval. Together with their friends and partners, Ana and Exra, they begin what they assume to be just another expedition, though if they don't return with the fame and fortune they seek, it may be their last. Instead of untold riches, however, they uncover evidence of an ages-old conspiracy that may have lasting influence in the modern world.

Caught in a struggle between secret societies and ancient eldritch forces, the pair races to a mythical island known as The Garden to stop a duplicitous cleric from gaining a power capable of untold destruction. Once there, they discover that perhaps the gods aren't as absent or benevolent as they thought, and everything they had assumed to be true may be a carefully constructed lie.

As they grapple with incomprehensible and fiendish beings to thwart the release of even more powerful forces - some whose loyalties and goals aren't yet certain - Lea is left with a vision of things to come that may include the death of her beloved Thomas and a brutal, nation-spanning war. It also becomes clear that someone may have been manipulating them from the start.