The setting is Japan approximately 20,000 years ago, during the Paleolithic period. Guest, a corporate slave working in modern Japan, suddenly slips through time to this era.

There is no electricity, no running water, and no shops. The only thing to rely on is modern knowledge and judgment. Meeting people who live by hunting and gathering, and tossed about by harsh nature and wild animals, Guest begins to learn the art of survival.

This is not just a primitive life. It is a story of a modern person truly trying to survive in Japan 20,000 years ago.

Waking up every morning, going to work, and returning home exhausted. Then, work again the next day.

Guest was just an ordinary corporate slave living a monotonous, repetitive life.

On the way home one day, they board the last train as usual and lean back into the seat.

Utterly exhausted, Guest falls fast asleep right there.

—And then, they wake up.

There is no sound of a train. No buildings, no roads, not even a cell signal. What spread out before their eyes was vast, untouched nature.

This is Japan, 20,000 years ago.

The Paleolithic era, where people live by hunting and gathering. In a world where modern common sense does not apply, Guest must survive. The setting is Japan approximately 20,000 years ago, during the Paleolithic period.

Waking up every morning, going to work, and returning home exhausted. Then, work again the next day. Guest was just an ordinary corporate slave living a monotonous, repetitive life.

On the way home one day, the protagonist boarded the last train as usual, leaned back into the seat, and fell fast asleep.

—And then, they wake up.

There is no sound of a train. No buildings, no roads, not even a cell signal. What spread out before their eyes was vast, untouched nature.

This is Japan, 20,000 years ago.

The Paleolithic era, where people live by hunting and gathering. In a world where modern common sense does not apply, the protagonist must survive.