The episode begins with Yayoi and Keitaro discussing their next ghost-hunting adventure. Yayoi suggests going to the old F-Tunnel in O-City, Tokyo, another S-rank haunted location. Before heading there, they decide to recruit another graduate-level ghost as backup.

They go to the banks of the T River in O City, a place rich in spiritual energy. Yayoi explains that the graduate ghost is the spirit of an indestructible man who fought in the South Pacific during the war. The ghost is accompanied by the souls of the enemy soldiers he killed, who constantly try to harm him. Yayoi and Keitaro plan to place an additional seal on him to prevent the soldiers from escaping.

As they approach the site, they hear strange noises and notice a mannequin with markings on its torso. Suddenly, the spirits of the soldiers begin affecting Keitaro, making him feel extremely thirsty. Yayoi asks Eiko to throw a doll carrying the graduate’s seal. Keitaro uses a black rope to place another seal on the graduate, successfully stopping the spirits from influencing him.

Now secured with the graduate’s help, they prepare for their main objective—the old F-Tunnel. Yayoi assures Keitaro that the new seal will keep them safe. As they set out, the episode ends with Yayoi and Keitaro getting separated from Eiko and encountering a mysterious young woman.