Jackson Oz, an American ex-pat safari guide living in Africa, discovers a link between strange animal attacks on people occurring around the world and his late father's controversial theories about an impending threat to the human race. Meanwhile, journalist Jamie Campbell and veterinary pathologist Mitch Morgan team up to investigate similar abnormal animal behavior in Los Angeles.
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 killing 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.
Jackson Oz and Abraham Kenyatta fly to Japan to recover the rest of Oz’s father’s research involving animals. Also, Jamie convinces Mitch to accompany her on a trip to her hometown in Louisiana to show a senator their findings on the abnormal behavior of the zoo lions. In Paris, Chloe is the first to be recruited by a shadowy intelligence agent, Gaspard Alves (Henri Lubatti), who is looking for the cause of the strange animal behavior, and a death row inmate escapes from a Mississippi prison after a vicious wolf invasion sets the prison ablaze.
Jackson, Abraham, Mitch, Jamie and Chloe are tasked by a top intelligence agent to find the cause of the strange animal behavior around the world. When the team travels to Mississippi to investigate the wolf attack on the prison, Mitch and Abraham break off to catch one of the wolves, and Chloe, Jackson and Jamie discover that death row inmate escapee Evan Lee Hartley might somehow be involved in the attack. Also, the team meets FBI Agent Ben Shafer, who may know more about the prison fire than he’s saying.
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.
While searching for a solution to the bat problem in Rio de Janeiro, Mitch and Chloe are kidnapped by the local drug lord and Abraham must come to the rescue. Also, reeling from the car crash that allowed escaped death row inmate Evan Lee Hartley to steal the one piece of evidence they had against Reiden Global, the Mother Cell, Jamie, Jackson and Agent Shaffer team up to track him down and lands Jamie in trouble with the FBI.
The team travels to Paris to search for a group of bears that were being studied for migration habits when their trackers mysteriously went offline. While investigating the strange occurrence, Chloe must work with and ultimately confront her ex-fiancé, a civil engineer, who is helping city officials find the missing bears. Meanwhile, with Jamie accused of murder, the team makes a daring plan to hack into the Reiden-Global mainframe, and Mitch makes a shocking discovery about the next evolutionary step of the animals.
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.
When Jackson is injured after a run-in with the rebels in Zambia, the team rushes him to a hospital in Zimbabwe and finds it overrun by wild animals. While Jackson undergoes emergency surgery, Mitch and Jamie work to formulate a cure using the Mother Cell and leopard DNA. Victory is within reach until a shocking turn of events jeopardizes everything.
After tragedy strikes their only ally within the government, the team is left on their own to stop a surge of animal-related attacks from destroying the city of Geneva, Switzerland. Also, new team member Dariela makes a shocking discovery about General Davies, head of the Noah Objective, and in the Canadian wilderness, Jamie witnesses the animals’ broadening effect on the environment and uncovers a troubling detail about Logan.
In an effort to unravel a dark conspiracy within the Noah Objective, the team travels to Vancouver, where it must infiltrate a black-tie event in order to get close to General Davies and stave off an impending animal threat. Also, Jamie and Logan’s journey is interrupted when Logan’s past comes back to haunt them.
With Jackson missing, Mitch and Abraham race to find him before General Davies and the International Animal Defense Group can locate him and prevent the team from making a cure. Also, Jamie, Dariela and Allison make a last-ditch effort to convince the Russian government to drop out of the Noah Objective.
It has been 10 years since mankind was sterilized. Along the West Coast, a huge barrier has been built to prevent the penetration of hybrids into the north of America. In this area, Jackson Oz as Dylan Green is working with Tess as a friend trying to get as many people as possible into safe zones. Abraham is working on a drug that would reverse the effects of gas. Aba and Dariel visit Clementine, daughter Mitche. She managed to get her evidence that her father was alive and that she was in the Siberian Stasi Chamber. Jamie is trying to get all the members of the Shepherd Organization responsible for sterilizing humanity and expanding hybrids, which is why he is in conflict with detective Logan.