The team discovers a terrifying rat infestation when a cargo ship carrying the bloodthirsty rodents washes up off the coast of Massachusetts. Also, unbeknownst to the rest of the team, Mitch reconnects with his terminally ill daughter in Boston as he prepares to make a trade with Reiden-Global to save her life.

In Botswana, guides Jackson Oz and Abraham Kenyatta come across a mysterious series of lion attacks. In LA, two lions escape a zoo and go on a rampage, and investigative reporter Jamie Campbell believes that it's tied to pesticide infested food sold by Reiden Global.

The team heads to Paris to investigate a group of bears whose trackers have gone offline. Mitch makes a shocking new discovery about the Mother Cell. Chloe runs into her ex-fiancé.

Jamie contacts a fellow journalist in an attempt to expose the truth about Reiden’s involvement in the global animal problem. After realizing Delavenne works for Reiden, Mitch escapes with both the Mother Cell and his daughter’s medication. However, on their way to deliver the medication, Mitch and Abraham come face-to-face with a terrifying army of birds.

Jackson discovers that Abraham is alive and stages a daring rescue to bring his friend home safely. Meanwhile, Jamie suspects that Reiden Global's pesticide is responsible for the lion attacks and convinces Mitch to help her. In Paris, a mysterious man approaches Chloe and asks her to accompany him.

Jackson and Abraham travel to Robert's isolated lab to recover his research. Meanwhile, Jamie convinces Mitch to go to New Orleans with her to approach a sympathetic senator, and Gaspald convinces Chloe to join forces with him.

On the run as fugitives, the team flies to Zambia to gather leopard DNA in order to manufacture a cure for the abnormal behavior that's affecting animals worldwide. When it’s time to leave, they need to reach out to animal rights activist Ray Endicott to get safe passage out of the country. Also, Chloe makes the ultimate sacrifice to avoid further bloodshed.

Jackson, Jamie, and Chloe travel to Mississippi to investigate the prison fire, while Abraham and Mitch go north to trap and study wolves.

Jackson, Jamie and Agent Shaffer search for a chemist in Alabama who has evidence of Reiden Global's role in the growing animal problem. Meanwhile, Chloe, Mitch and Abraham fly to Rio de Janeiro to delay the local government's plan for a massive bat extermination and come up against a ruthless drug lord.

Abraham works to save Chloe and Mitch from a drug lord; Jackson and Jamie continue to work with Agent Shaffer in search of Evan Lee Hartley and the Mother Cell after Leo is killed in the crash.

Chloe tries to bring light to the rising threat from the animals. Jackson is taken to a hospital and while they are there Mitch works to create a cure. However, there are many obstacles they must overcome.

Jackson and the team make a final attempt to find a cure to the worldwide animal pandemic, but hit an obstacle that may be impenetrable.

Chloe is taken hostage by someone she knows. Jackson and the others are arrive at Zambia to find the leopard to test Mitch's theory of the animal mutation.