Merritt Voss survives three months of the collapse, then dies in a quarantined shelter, listening to the last broadcast of Tessa Rourke, the clinic technician who once patched him up and told him not to treat one day as the rest of his life. He wakes instead twelve hours before the first wave, both legs whole, the harbor still ordinary. He knows what the next three months cost, so he borrows nine hundred thousand dollars against both apartments, turns it into food, water and steel, and seals his top floor behind a vault door before the power fails. He also cuts off Brielle, whose access code once opened his door to the men who took his leg, and her brother Colby, still waiting for dinner downstairs. The only warning he gives is to Tessa, a stranger to him: stay inside. Then the outbreak starts and strands her below him with a young woman named Greer. Within a day the building votes to seize his stockpile, and the only sealed door in Cinder Quay must decide who lives behind it.
