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.

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.

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.

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.