Three men, each from different walks of life, decide to embark on a unique and intense competition known as a "Big Year," where birdwatchers try to identify as many species of birds in North America as possible within a calendar year. Brad Harris, a software engineer, is struggling with a lackluster career and a disappointing personal life. To break free from his routine, he decides to follow his passion for birdwatching. Stu Preissler, a wealthy and recently retired CEO, sees the competition as a last hurrah before fully committing to retirement and spending time with his family. Lastly, Kenny Bostick, a contractor with competitive zeal, aims to set a new bird-spotting record, despite the strain it puts on his marriage.

As they travel across the continent, each man faces various challenges and discovers different aspects about themselves and their lives. Their journeys take them to remote and stunning landscapes, creating opportunities for encounters with rare and beautiful birds. The pursuit leads to surprising friendships, fierce rivalries, and moments of introspection. Through the highs and lows of their birdwatching odyssey, the participants learn invaluable lessons about ambition, relationships, and what truly matters in life.