Boog, a domesticated 900lb. Grizzly Bear finds himself stranded in the woods 3 days before Open Season. Forced to rely on Elliot, a fast-talking mule deer, the two form an unlikely friendship and must quickly rally other forest animals if they are to form a rag-tag army against the hunters.
One night, Bob and Bobbie leave their trailer to go skinny-dipping, leaving Mr. Weenie to guard the cinnamon buns they left on the counter. Boog and Elliot sneak into the camp and discover there's buns in trailer. Unfortunately, Weenie is guarding the door.
After falling head over hooves in love with Giselle, Elliot's road to the altar takes a slight detour when Mr. Weenie is kidnapped by a group of pampered pets determined to return him to his owners.
When Boog's pals choose their family obligations over the annual guy's trip, a disappointed Boog takes a trip of his own, which leads him right into the middle of a circus ring. When he switches places with a devious look-a-like circus grizzly and falls for an alluring Russian troupe member, his friends rally to bring him home.
The film opens with Elliot telling a campfire story about the legend of the Wailing Wampus Werewolf that lives in Timberline National Forest. Domesticated Boog is terrified by the story and decides to "chicken out" of their annual summer camping trip until he knows the werewolf is gone. Determined to help Boog overcome his fears, Elliot, Mr. Weenie and their woodland friends band together to scare the fear out of Boog and uncover the mystery of the Wailing Wampus Werewolf.
When Boog and Elliot discover an abandoned Summer Camp in the middle of nowhere, they embark on a brave new adventure of creating a safe and special place to live that welcomes animals of every kind. Under the leadership of Boog and Elliot, the Campers must all work together to help create their own slice of paradise in the middle of the wilderness and rediscover their inner wild.