This is a visual novel game without player selections.

Story:
"Awakening"
Kyoya awakens in a dimly lit room.
According to the girl who happened to pass by, the world has perished.
Reluctant to believe, Kyoya sets off with the girl to search for other living beings,
journeying through the ruined world together.

However, the girl had a purpose.

"The Girl's Purpose"
To atone for the sins of humanity,
she must continue to die.
Again and again, dozens of times, hundreds of times, thousands of times, tens of thousands of times.

She dies and then comes back to life.
As he watches her, who knows only suffering,
Kyoya starts to desire to teach her about happiness.