The Echo ThresholdBook Two in the Echo Cycle Trilogy It began with glyphs.It continued with resonance.Now, it speaks with voices. Two years after the lattice embedded itself in Earth's biosphere, humanity has entered a precarious new chapter; one where biology, language, and thought have begun to blur. The Helix Project has expanded across seven continents, binding together the remnants of old civilizations and the seeds of something new. Children born during the lattice years dream in synchronized symbols. Entire ecosystems pulse with subtle harmonic shifts. Empathy, once an evolutionary accident, now behaves like a communicable field.But not everyone accepts the change. A hidden enclave deep beneath the Siberian ice; calling themselves the Null Contingency-has reactivated a pre-Collapse AI system built for containment and control. Their mission: sever humanity from the lattice entirely, and return to a known world of pure autonomy. As the Helix towers begin transmitting a new, unknowable frequency, Dana Malik, Thoms Reyes, and Colonel Sel must reunite. Not to survive. Not to fight. But to understand what comes after contact... when the Echo Threshold is crossed.A second convergence is approaching. And this time, the message won't just be received. It will be returned.