After Jackson Oz rescues his best friend, Abraham Kenyatta, from a lion attack in Botswana, Abraham's firsthand account of the attack reveals that the lions are no longer afraid of humans and might be hugging for sport. Also, Jamie and Mitch run tests on a lion cub in the Los Angeles Zoo and uncover a link to a chemical made by a biotechnology company, and Chloe Tousignant returns to Paris where she must overcome her own trauma and focus on her work as a government intelligence analyst.
Zoo is set amidst a wave of unhappy animal attacks sweeping across the planet. A young renegade scientist is thrust into a race to unlock the mystery behind this pandemic before time runs out for animals and humans alike.