At the End - a post-apocalyptic novel

This title is no longer available. Night 1: 12 billion taken. Day 1: Confusion. Night 2: 13 billion taken. Day 2: Panic. Night 3: 13 billion taken. Day 3: The fight for survival begins. In 2048, the human population borders 39 billion after the termination of the birth control industry, and the realities of overcrowding have sunken into the minds of the world . . . until billions mysteriously go missing. In the wake of civilization's collapse, a trio of teenage gamers from Washington struggle to endure. Maggy, a strong-willed intellectual, leads Darrel and Félix, two shy geeks, on an expedition down the west coast, as they search for answers about the source of humanity’s downfall, determined to survive the deadliest threat the Earth has ever known. A fast-paced post-apocalyptic sci-fi novel geared toward teen+