Walter Black, portrayed by Mel Gibson, is a man trapped in the depths of despair, spending his days engulfed in depression. This dark state drives his family to their breaking point, leading his wife, Merideth, to make the difficult decision of kicking him out. Their youngest son, Henry, is incredibly introverted, while his older brother, Porter, is desperately trying to avoid following in Henry's footsteps.
In an unexpected turn, Walter adopts a beaver puppet, which he initially uses as a means to communicate with himself while grappling with suicidal thoughts. However, this quirky decision soon evolves as Walter begins to use the puppet to engage with others, embarking on a journey to rediscover his purpose and rebuild his fractured life. Merideth eventually invites him for dinner, marking a potential reconciliation.
Through the beaver, the family starts to uncover the complexities of Walter's past and the challenges he faces. Despite their concerns, Porter is convinced that his father's behavior is nothing short of insanity. Soon enough, the beaver character becomes part of Walter's professional life, bringing fresh ideas to his company based on Henry's woodworking interests, ultimately leading to a successful line of woodworking kits.
Amidst these developments, Porter is approached by Norah, played by Jennifer Lawrence, the high school's valedictorian who enlists his help with her graduation speech. What starts as a simple collaboration blossoms into romance as they navigate their feelings, but they quickly find themselves on the wrong side of the law after a graffiti escapade. In parallel, Merideth and Walter attempt to reconnect over dinner, but the conversation falters until Walter reintroduces the beaver into their dynamic. After a chaotic night that leads to Porter's arrest, Merideth decides they must distance themselves from Walter’s beaver persona.
The beaver gains immense popularity, even making an appearance on the Today Show where it shares insights about breaking free from depression, prompting Walter’s family to start understanding his struggle. However, this newfound fame brings challenges, as Walter's attempt to reconnect with Merideth is met with aggression from the beaver, leading him to take drastic measures.
As the story unfolds, Walter's situation deteriorates, resulting in a crisis that lands him in the hospital. With Porter now mirroring his father's patterns, both are caught in a troubling cycle of despair. When Norah offers Porter a glimmer of hope by revisiting their relationship, he finds inspiration in her efforts to help him mend his bond with his father.
Ultimately, the narrative resonates with themes of renewal and understanding, culminating in Porter’s realization of the importance of family reconciliation.