The zoo is nearly empty as Joan and her four-year-old son happily soak up the last few moments of playtime. But what Joan sees as she hustles her son toward the exit gate minutes before closing time sends her sprinting back into the zoo, her child in her arms. And for the next three hours, she keeps on running, barely a step ahead of danger. NPR praised this thought-provoking thriller as "a terrifying book, but more importantly, a beautiful one."