"Tiger & Bunny the Movie: The Beginning" serves as a recap and reimagining of the first two episodes of the original "Tiger & Bunny" anime series, with additional scenes and enhanced animation. The story is set in Stern Bild City, a metropolis where superheroes, known as NEXT, work for corporate sponsors and compete for points by capturing criminals, all while being broadcast on a popular reality TV show called "Hero TV."

The protagonist, Kotetsu T. Kaburagi, also known as Wild Tiger, is a veteran hero whose old-fashioned methods and declining popularity have left him struggling to stay relevant. His life takes a turn when he is forced to partner with Barnaby Brooks Jr., a young, efficient, and highly skilled hero with a mysterious past. Barnaby, who goes by the alias Bunny, has a personal vendetta against the criminal organization Ouroboros, which is tied to the murder of his parents. Despite their clashing personalities and approaches to heroism, the two must learn to work together as a duo.

The narrative explores their early partnership, highlighting their initial friction and gradual development of mutual respect. A significant portion of the film focuses on their first major mission together: thwarting a bank robbery orchestrated by a group of NEXT criminals. During this mission, the duo faces challenges that test their abilities and force them to rely on each other. The film also delves into Barnaby's backstory, revealing his motivations and the trauma that drives his relentless pursuit of justice.

Key supporting characters include the other heroes of Hero TV, such as Blue Rose, Rock Bison, Fire Emblem, and Sky High, each with their own unique abilities and personalities. The corporate dynamics of Hero TV and the influence of sponsors on the heroes' actions are also explored, adding depth to the world-building. The film balances action-packed sequences with moments of character development, providing a cohesive introduction to the "Tiger & Bunny" universe.

By the end of the movie, Kotetsu and Barnaby begin to form a tentative partnership, setting the stage for their future adventures. The film effectively condenses the core elements of the series while offering new insights and polished visuals, making it accessible to both newcomers and fans of the original anime.