Bruce Wayne, operating as Batman, is a vigilante crime-fighter from Gotham City. Caught in Gorilla Grodd's time displacement machine during a confrontation at Arkham Asylum, he arrives in feudal Japan two years after other Gotham characters due to his position relative to the machine. This delay enables Gotham's villains to establish themselves as feudal lords, with the Joker ruling supreme. Initially reliant on advanced technology like the Batmobile and grapple gun, he struggles as these tools prove ineffective in the new environment; the grappling hook fails against low Japanese huts, forcing a shift in approach. He adapts by embracing feudal-era methods, training in ninjutsu and sword-fighting under the Bat Clan of Hida, who worship him as a prophesied figure destined to restore order. This training hones his martial arts, acrobatics, stealth, and deception, culminating in his adoption of a Bat-Sword as primary equipment.
He reunites with allies Catwoman, Alfred Pennyworth, Nightwing, Red Hood, Red Robin, and Robin. Alfred establishes a makeshift Batcave outside Edo, and the Bat Clan aids the Bat-Family based on their prophecy. Bruce coordinates efforts to retrieve the time machine's power converters from various villains, forming a temporary alliance with Gorilla Grodd. He encourages the Bat-Family to learn ninja techniques, integrating their abilities with local strategies. Demonstrating care for civilians, he risks himself to save a mother and child later revealed as Harley Quinn in disguise.
In the climactic battle at the "Field of Hell," he leads the Bat-Family and Bat Clan against the united villains. After Gorilla Grodd betrays him and seizes control, Bruce accepts command of Grodd's army of monkeys following Grodd's injury. This forces a final confrontation with the Joker, who merges the villain castles into a giant robot. Robin uses a flute to direct the monkeys, merging them into a giant samurai monkey that fuses with bats to form the "Batgod." Bruce engages the Joker in a sword fight, defeating him using his ninjutsu skills. This victory allows the Bat-Family to return the villains to the present, where James Gordon apprehends them.
Following the return to modern Gotham, he attends a mayoral party in a tuxedo, arriving in a horse-drawn Batmobile, indicating retained elements of his feudal experience. His actions in feudal Japan underscore a stern yet protective personality, prioritizing the safety of allies and civilians while adapting to extreme circumstances.