"Sengoku Yankee" is a manga series that blends historical elements with modern cultural influences, creating a unique narrative set in a reimagined version of Japan's Sengoku period. The story centers around a group of delinquents from the modern era who are mysteriously transported back in time to the warring states period. These characters, embodying the rebellious spirit of "Yankee" culture, find themselves navigating the chaotic and violent landscape of feudal Japan.

The protagonist, a tough and street-smart delinquent named Jiro, becomes the de facto leader of the group. His resourcefulness and combat skills, honed in the rough neighborhoods of modern Japan, prove surprisingly effective in the Sengoku era. Alongside Jiro are his close friends and fellow delinquents, each with distinct personalities and abilities that contribute to their survival and influence in this unfamiliar world. Their modern sensibilities and unorthodox methods often clash with the traditional samurai ethos, leading to both conflict and unexpected alliances.

As the group adapts to their new environment, they become entangled in the power struggles between various warlords and factions. Their presence disrupts the historical timeline, introducing modern tactics and ideas that alter the course of battles and political maneuvers. The narrative explores themes of loyalty, honor, and the clash between tradition and innovation, as the characters grapple with their roles in shaping the future of Japan.

Key historical figures from the Sengoku period, such as Oda Nobunaga and Toyotomi Hideyoshi, are reimagined with interactions that highlight the tension between the old and new worlds. The delinquents' journey is marked by intense battles, strategic alliances, and personal growth, as they navigate the complexities of feudal society while striving to find a way back to their own time. The series balances action-packed sequences with moments of introspection, offering a dynamic portrayal of its characters' struggles and triumphs in a turbulent era.