Su Mu, a hundred-year-old man, cannot bear to let his granddaughter travel far away to the battlefield, so he resolutely enlists in her place. An elderly commoner enters the military camp and is initially subjected to endless contempt, with no one believing in this old man nearing the end of his life. But when the flames of war ignite, he reveals his long-hidden, unparalleled military strategies, devising brilliant battle plans and defeating powerful enemies. Qin Hao initially doubts him, but eventually becomes thoroughly convinced and follows faithfully at his side. Armed with his extraordinary strategic wisdom, the old man sweeps away foreign threats and protects the peace of the people. From an ordinary veteran, he gradually forges a legend and rises to become the revered God of War Who Guards the Nation.