Set in the final decades of Japan's chaotic Sengoku period, Kaze no Yari chronicles the life of Honda Tadakatsu, a legendary spearman who serves Tokugawa Ieyasu from the warrior's youth. The story opens in Mikawa Province, where the young Tadakatsu begins his career as a retainer of the Matsudaira clan, newly renamed Tokugawa. The central conflict revolves around survival and loyalty in a violent era dominated by shifting alliances, betrayal, and near-constant warfare. For Tadakatsu, the essence of life is to feel the wind, a philosophy that guides him through countless battles where he must decide what to preserve, his life, his honor, his lord, or his land, when he cannot protect everything at once.

The narrative follows the major historical events that shaped Tadakatsu's reputation. At the Battle of Okehazama, the allied Matsudaira forces are cornered by Oda Nobunaga's army, and Tadakatsu is assigned to lead a supply convoy to the besieged Kaminokō castle, receiving unexpected news that changes the course of the operation. In the aftermath, Tadakatsu pursues a new spear, commissioning the legendary smith Fujiwara Masazane to forge a blade, a quest that proves more difficult than expected. He eventually gains the famed spear Tonbokiri, one of the three great spears of Japan. The formation of the Kiyosu Alliance sends Tadakatsu and his lord to Owari Province to negotiate a pact with Nobunaga himself, a high-stakes diplomatic mission that tests Ieyasu's resolve.

As prolonged warfare devastates Mikawa, the Ikkō-ikki uprising erupts across the province, with peasants revolting and former allies turning against the Tokugawa. Facing the worst crisis in the domain's history, Tadakatsu vows to fight without killing, a brutal challenge in a civil war that makes brothers kill brothers. The uprising reaches its resolution as Tadakatsu finds a way to endure the slaughter. Later, at the Battle of Anegawa, Tadakatsu faces the formidable Takeda cavalry in a desperate fifty-on-three hundred charge, struggling to protect Ieyasu against overwhelming odds while Oda Nobunaga continues his advance on Kyoto, a period where loyalty and betrayal collide.

The story reaches its most intense crisis in 1572, when Takeda Shingen, the Tiger of Kai, invades Tōtōmi Province aiming for the capital. Ieyasu's army faces total destruction as Shingen's meticulously planned strategies force Ieyasu into a gamble. The decisive Battle of Mikatagahara erupts, a fully committed confrontation where the Tokugawa army is caught between calculated Takeda tactics and sheer desperation. Tadakatsu, burning for vengeance with a blood-soaked spear, charges into the fight, carrying the fate of the Tokugawa clan on his blade as he tries to reach the Takeda general Yamagata Masakage and Shingen himself.