The sun breaks over the forest, heralding the arrival of spring and a fresh chapter in the life of Boog (voiced by Billy Bob Thornton). After spending several years in hibernation, the lovable opossum is eager to reconnect with his past by organizing an annual guys' trip. However, Boog quickly realizes that things have changed dramatically; his friend Elliot (voiced by Johnny Flynn) has started his own family with Giselle, and their days of carefree adventures are now distant memories. As Elliot juggles the responsibilities of fatherhood for their lively trio of offspring—Giselita, Giselita Jr., and Elvis—Boog finds himself feeling increasingly isolated and searching for purpose in a life devoid of romance or children. With only his stuffed toy companion Dinkleman to accompany him, his plans for the guys' trip turn into a solitary journey.
During his wandering, Boog uncovers a hidden gem: the Maslova Family Circus, a vibrant group of performers beloved by the local wildlife. Within this colorful troupe is Doug (voiced by Ewen Bremner), a self-absorbed grizzly bear feeling overlooked and eager to claim his title as the king of the forest. In a cunning twist, Doug manipulates Boog into swapping their identities, promising to bring his friend Alistair (a charming Argentine camelid) back to the forest. Yet as the plot thickens, it's clear that Doug has no intention of fulfilling his promise and instead exploits Boog's guise to dominate the wildlife.
As Boog navigates this lively circus world, he soon realizes Doug's true intentions. Despite feeling betrayed, he develops a compassionate bond with Alistair, as they both share a sense of abandonment from their best friends. As the saga unfolds, Boog must confront his feelings of loneliness and grapple with the search for his new life direction. Amidst the exuberance of the circus, he finds himself enchanted by Ursa, a remarkable Russian-born grizzly bear whose extraordinary talents leave him breathless. Her deftness on the tightrope and graceful juggling appeal to Boog, who affectionately dubs her performances "bearvana." Unfortunately, Ursa initially regards Boog (who is masquerading as Doug) with disdain, still haunted by his prior selfishness.
Determined to prove his true identity, Boog takes on the challenge to scale the high wire. After successfully completing the feat, Ursa reveals she recognized him from the start—an ability that transgressed Doug's limitations. Despite her skepticism, Ursa gradually softens as Boog shares stories of his journey. He wins her over with his kindness, distinguishing himself from Doug and other grizzly bears who often exhibit hostility.
As the plot thickens, Mr. Weenie and his quirky crew—along with the reformed Fifi and newcomer Nate—witness Boog's circus advertisement and suspect foul play, leading them to rally for a rescue mission. After outmaneuvering a gas station attendant and commandeering Bob and Bobbie's RV, they make tracks for the circus grounds. Simultaneously, Giselle and the cubs uncover Doug's deception, rallying the community to support Elliot as he leads the charge to save Boog before the circus departs for Russia.
Amidst rising tension, Boog stands at a crossroads: pursue his affection for Ursa or reunite with his forest friends. Recognizing Boog’s happiness with Ursa, Elliot and the gang encourage him to follow his heart. Boog extends an invitation for Ursa to join him in the forest. She contemplates and ultimately agrees but realizes that a circus without its star bear is merely a shadow of its potential.
In a surprising twist, Doug returns with an apology, reuniting with Alistair. With Ursa's consent, Boog and his friends set off toward their new adventure in the forest, embracing a life enriched by her presence. Ursa assumes the role of Boog’s partner and becomes an honorary aunt to Elliot and Giselle’s children. The group's friendship deepens as they embark on an annual guys' trip, joyfully crooning along to Willie Nelson’s "On the Road Again" as they revel in the beauty of nature.
Meanwhile, Mr. Weenie and his gang venture to Devils Tower in a quest for extraterrestrial encounters, while the circus crew begins their long trek back to Russia. The film wraps up with Doug and Alistair sharing an endearing slideshow documenting their escapades across the globe, cementing their enduring friendship as they journey home.
