Ten years after the Pacific War, four ex-soldiers—Onuma, Takeshi Katô, Nakata, Kō Nishimura, Yamamoto, Shinichi Yanagisawa, and Sawai, Shoichi Ozawa—team up to recover a hidden stash of morphine said to be buried in an air-raid shelter. Their only reassurance comes from a former superior who claimed that only three men knew about the morphine, so a seed of doubt quickly takes root and Sawai becomes the initial prime suspect of an intruder in their tightly knit group.
The shelter’s surroundings have transformed into a bustling shopping district, while the shelter itself now lies beneath the basement of a butcher shop. To move forward, the group rents an empty store from the corrupt local landlord Kinzo, Ichirô Sugai, and begins digging a tunnel that would connect them to the basement below. The tension among the four men heightens when Shima, Misako Watanabe, arrives and declares that she is the younger sister of the Lieutenant who has died in the meantime, adding a personal edge to the already volatile mission.
Shima’s presence further complicates the dynamics: she promises intimacy to the man who digs up the most, and her attractions lead to a dangerous triangle that involves Kinzo’s son Satoru, Hiroyuki Nagato. Satoru himself attempts to court the butcher’s daughter Ryūko, Sanae Nakahara, weaving romance into the grim backdrop of a race against time and a life-or-death mission.
As the dig continues, trouble from outside looms: Yamamoto is arrested for burglary, but he manages to escape and returns to the group’s dwindling circle. His violent bravado culminates in an attempted rape of Shima, an act that Sawai sooner or later opposes, highlighting the fragility of trust among men whose pasts have already bled into the present.
Time becomes the cruel enemy as Kinzo announces that the entire area will be demolished within days by a city decree, turning the dig into a frantic scramble to reach the basement before it’s erased. In a brutal turn, Sawai kills Yamamoto, yet is himself buried alive beneath sand when the group, having already breached the basement, leaves him behind in the shifting debris.
With only Onuma, Nakata, and Shima remaining, a startling revelation comes to light: Shima is the widow of Lieutenant Hashimoto, and Nakata—who has been digging alongside them—turns out to be the intruder whom they had suspected all along. The two had previously been charged with Hashimoto’s death but were released for lack of evidence, a detail that deepens the sense of betrayal that now festers within the trio. Shima poisons Onuma and then stabs Nakata, intent on claiming the morphine for herself.
Satoru, witnessing the chaos, calls the police as the situation spirals toward a fatal conclusion. In the ensuing pursuit through a heavy rain, Shima slips on a slick crossing and drowns in the river running beneath, leaving the morphine—and the mystery—to rest in the murky depths of what remains. A tense chase, moral ambiguity, and the relentless pull of survival characterize a story where loyalty, greed, and regret collide in the wake of war.
