The remaining, Book 1 / D. J. Molles.
(Book)

In a steel-and-lead-encased bunker 20 feet below the basement level of his house, a soldier waits for his final orders. On the surface, a plague ravages the planet, infecting over 90% of the populace. The bacterium burrows through the brain, destroying all signs of humanity and leaving behind little more than base, prehistoric instincts. Someday soon, the soldier will have to open the hatch to his bunker, and step out into this new wasteland, to complete his mission: to rescue and rebuild.