The private jet sliced through low clouds above the Arctic waters, its matte-gray frame nearly invisible against the bruised dawn. Emma sat across from Jack in the dim cabin, each strapped in, silence weighing heavier than the frost forming on the window. The tension between them was palpable, thick with unresolved truths and a growing dread neither could admit aloud.

Coordinates from the anonymous letter had led them here—to an unnamed island just south of Iceland, shielded by international ...