Chito and Yuuri, two resilient young girls, find themselves adrift in the aftermath of a catastrophic war that ravaged the entire Earth. With heavy hearts, their adoptive grandfather exiled them to the unforgiving wasteland beyond, leaving behind the shattered remnants of their former lives.

Armed with a Kettenkrad filled with basic needs, Type 38 Arisaka Rifle, military uniform, and the enigmatic words of their grandfather etched in their minds - "Climb Up The Tower Beyond, Do Not Go Down". Chito and Yuuri have been navigating the desolate, crumbling cities in search of a sanctuary that may still endure atop the highest reaches of the metropolis.

Their journey has brought them into contact with a survivors, each with their own tales of hardship and ingenuity. The first was a man named Kanazawa, whom blow up a building to serve as a precarious bridge over an expansive gorge dividing two city blocks. Though his impromptu crossing nearly claimed the girls' lives, a fragile alliance was forged. Before parting ways on a higher level, Kanazawa bestowed upon Chito a vintage camera, a gift she's come to cherish and use frequently to capture the haunting beauty of their post-apocalyptic world.

The second survivor - Ishii, was a woman with an unyielding ambition to soar into the skies with a plane. She took pity on the girls whom Kettenkard broke down and offered to fix it alongside taking them refuge, hearty meals, and the simple luxury of a hot bath. In exchange, Chito and Yuuri lent their hands to assist in the construction of a plane. With bathed breath, they watched as the makeshift aircraft took flight, only to witness it disintegrating 40 seconds after take off. Though Ishii survived the cataclysmic failure with a parachute, she plummeted to the lowest level of the city, her fate afterwards was unknown to the two.

Chito gripped the steering wheel lightly as she navigated the dilapidated Kettenkrad through the desolate streets. The engine rumbled beneath them, a comforting constant in the eerie silence that hung heavy over the ruined city. She kept her eyes narrowed, scanning the crumbling buildings and debris-strewn roads for any signs of danger or, more desperately, signs of foods.

Yuuri lounged in the back, her rifle resting across her lap as she gazed out at the bleak landscape rolling by. Her finger absently traced the cool metal of the barrel, She watched the skeletal remains of once-grand buildings crumble into dust in the distance, their silhouettes stark against the ashen sky. A question bubbled up in her mind, She leaned forward, resting her elbows on the back of Chito's seat as she asked Chito's a question.

[Yuuri] -- "Chi, what do you think awaits for us at the highest level of this city? Do you think there'll be people's living happily?"

Chito's didn't take her eyes off the road, instead staring ahead at the cracked and broken asphalt stretching out almost endlessly before them.

[Chito] -- "Beats me..."