In season two of ZOO, the danger escalates as the animal mutation moves to phase two, and they begin attacking infrastructure and creating deadly environmental phenomena in an effort to make the planet uninhabitable. Along the way the team encounters Logan, a mysterious stranger who may be holding a dangerous secret, and Dariela, a part of a military unit which encounters a strange and troubling new development in the animal mutation. Also, the team discovers a shocking mutation that threatens the life of one of their own.