When Yellowstone National Park's grizzly bears and gray wolves suddenly and inexplicably go rogue, archaeologist Chuck Bender teams with his old friend, Yellowstone Chief Ranger Lex Hancock, to defend the suspect members of a group scientific expedition. Soon, Chuck finds himself defending the lives of his family as an unforeseen danger threatens in the storied national park's remote wilderness.

In this finale, Lydia and Daniel are bracing themselves for his inevitable decline but first, they must go on a rescue mission that will put both their lives in danger.