"If one day the stars really disappear, then... Will you still stay with me?"
"What are you talking about? Even if the stars really disappear, I will always be with you."
In 3000, the "Life 2" potion studied by humans reached the state of immortality, and research is still ongoing...
…
In 3056, the earth still collapsed due to being overwhelmed.
The earth that was once full of vitality has become dusty and foggy, and there are no patches of green shade in sight...
The green mountains and green waters of the earth have become [past] and [history].
Purpose: Care for the environment and protect the earth.