Wandering the wrecked wagons of the train, he finds Nobuo Takahashi (高橋 のぶお), a highly unnerved boy who apparently was being bullied at school, and Ako Seto (瀬戸 憧子), who is unconscious and wounded.
Nobuo's mental state deteriorates to the point where he claims the wrecked train for himself, forcing Teru and Ako to build a makeshift shelter outside in the tunnel.
After days pass with no sign of rescue, Teru tries to find an escape route and ventures into a partially collapsed ventilation shaft.
In the chaos, amidst falling rocks and choking steam, Teru notices Ako being chased by a crazed Nobuo and comes to the girl's rescue.
Ako and Teru initially follow this group to Tokyo, but decide to leave after witnessing them wounding themselves and dancing amidst dead cattle.
Aboard the helicopter are Captain Nimura (仁村), pilot Iwada (岩田), and crewmen Yamazaki (山崎) and Ōike (大池).
While Iwada seems to be a voice of reason, Nimura is an unprofessional loose cannon and chases away Teru when he begs them for help.
Seeing Yamazaki return wounded and now knowing there's a girl in town, Nimura and Ōike grab their guns and start searching for her.
The stress of the situation, the urge to defend Ako and the hatred for the soldiers briefly cause Teru to "give in to the darkness" as Nobuo did, preparing a Molotov cocktail in hiding.
At the schoolyard where the helicopter landed, Iwada and Ako take off, leaving Yamazaki behind to be burned alive enormous fire tornadoes.
Because it's impossible to fly directly through the cloud without damaging the helicopter's engine, they decide to take a detour through the Izu peninsula.
The next day, they find mutilated bodies at a nearby lake as well as a frightened young man and his companion, a seemingly disabled boy with strange scars on his head.
The silent boy gets badly burned on his arm, but incredibly doesn't make a sound, as if completely numb to pain.
This isolation has left the survivors without food and, due to the dire circumstances, has driven them to go mad and murder their relatives, with plans to stage a mass suicide.
Fortunately, Nimura, Ako, and the scarred boy, Kikuchi, manage to escape from the mob, though they can't leave town.
As the town is completely engulfed in the massive cloud, a townsperson ignites the pyre and blows the building up, burning to death with the other survivors.
As they fly away, Teru's group sees Kikuchi on the rooftop, on fire and showing no expression, a sight that greatly disturbs Ako.
Remembering the words from Kikuchi, Ako reaches a nearby building where, reading through some books, manages to link the "painting" he spoke about to Mount Fuji.
Considering the environmental conditions, the group theorizes that Mount Fuji had either suffered a catastrophic volcanic eruption or had been hit by a meteor.
In the ensuing chaos, Iwada, Ako, and Nimura manage to take off in the helicopter while the roof of the mall collapses beneath Teru.
Although initially overcome by despair, Teru looks inside the helicopter and finds and a note from Ako, which tells him that she and Nimura are heading for Tokyo on foot.
Terrified, Teru goes even deeper, and finds himself in a massive warehouse where a group of survivors, led by a self-declared scientist, have stockpiled supplies.
After consuming them for a prolonged period of time, the survivors of his group stopped feeling fear completely and, longing for it again, started wounding themselves.
Meanwhile, the scientist's group attacks a patrol of foreign soldiers, and a fleet of ships from another country is seen anchored in what was once Tokyo Bay.
A document discovered by other soldiers indicates that three nuclear weapons were on Japanese soil, that the governments of Japan and other nations have vanished, and that no one seems to know what exactly caused the catastrophe.