During a defensive exercise, a wildly mixed Japanese SDF unit—carrying a tank, an APC, a patrol boat, and a helicopter—suddenly find themselves stranded 400 years in the past by a time-slip event, and they come under attack from samurai forces. This shocking shift thrusts them into a brutal, unfamiliar world where survival hinges on adaptability and cooperation with feudal powers.
Leading the response is Second Lieutenant Yoshiaki Iba [Sonny Chiba], who quickly forms an uneasy alliance with Nagao Kagetora [Isao Natsuyagi], the ambitious war leader allied with lord Koizumi. Seeing the SDF’s modern firepower in action, Kagetora persuades Iba to aid him in his struggle for supremacy in feudal Japan, blending cutting-edge technology with traditional warfare to tilt the balance in their favor.
Back home, Iba faces a growing morale crisis among his men. Some desperately seek a way back to their own time, while others forge local connections—one Private First Class Mimura even finds himself followed by a consort who clings to him. As orders blur and tensions rise, a portion of the unit rebels or slips into a pirate mentality, and the group’s numbers dwindle from twenty-one to eleven. Iba tries to steady his weary troops, suggesting that by fighting history they might carve a path back to their own era, a paradox that keeps hope flickering amid the chaos. Eventually, Iba commits to the alliance with Kagetora and fights beside him against a common foe.
The united force then confronts Takeda Shingen’s formidable army. Shingen’s forces outmaneuver them at every turn, stripping away their vehicles and major weapons, and leaving a trail of casualties as five soldiers fall in the brutal exchanges. In a bold, defining move, Iba pushes through to Shingen’s command post and kills him in a sword duel, a moment that shifts the momentum but also tightens the political noose around Iba and his allies.
As Iba’s band advances toward Kyoto, Kagetora comes under pressure from his own family and the Shōgun Ashikaga Yoshiaki [Mizuho Suzuki] to rid himself of Iba. Reluctantly, Kagetora intercepts Iba’s group at an old temple. When Iba prepares to end the alliance by killing Kagetora, Kagetora shoots him instead, and the remainder of Iba’s men are felled by Kagetora’s archers. Mimura’s consort delivers the fatal blow to her lover, sealing a tragic turn in their unlikely alliance.
In a somber denouement, Kagetora buries Iba and his surviving soldiers with honors. Only Mokichi Nemoto [Hiroshi Kamayatsu], who had left the group to aid a boy and his family after their father’s death, survives the ensuing storm of history, a small flicker of hope amid the vast, unresolved march of time.
