When the alien Hussqa arrive offering life-extending biotech and advance technologies, Earth welcomes them. Grieving Navy officer Ben Sumner is assigned to do more than chaperone a brilliant Hussqa geneticist, he’s tasked with uncovering what they’re not telling us. As Ben navigates growing intimacy with Mila, he discovers fractures within the Hussqa themselves, some, like Mila and Alys, the Hussqa leader, seek coexistence. Others, like the sociopathic serial killer, Viridian, believe in Hussqa dominance.

Meanwhile, across centuries and timelines, ancient memories, buried technologies, and past lives begin to surface. From an ancient and hostile Hussqa secret society to a Palaeolithic boy’s vision of a celestial arrival, one truth becomes clear: Earth’s history isn’t what we thought, and the Hussqa’s presence may not be what it appears.

Told through intersecting stories of loss, survival, and quiet resistance, What We Leave Behind explores the price of immortality, the danger of unchecked trust, and humanity’s place in a larger, older galactic design.