Planetarian: Ultimate Edition

Planetarian: The Reverie of a Little Planet
"Why don't you come to the planetarium?
The beautiful twinkling of eternity that will never fade, no matter what.
All the stars in the sky are waiting for you."

It is thirty years after the failure of the Space Colonization Program.
Humanity is nearly extinct. A perpetual and deadly Rain falls on the Earth.
Men known as "Junkers" plunder goods and artifacts from the ruins of civilization.
One such Junker sneaks alone into the most dangerous of all ruins -- a "Sarcophagus City".
In the center of this dead city, he discovers a pre-War planetarium.
And as he enters he is greeted by Hoshino Yumemi, a companion robot.
Without a single shred of doubt, she assumes he is the first customer she's had in 30 years.
She attempts to show him the stars at once, but the planetarium projector is broken.
Unable to make heads or tails of her conversation, he ends up agreeing to try and repair the projector...

Planetarian: Snow Globe
This story occurs before the events of the war that brought the world to ruin; at this point, Yumemi has been working at the Flowercrest Department Store's rooftop planetarium for about ten years. One day, Yumemi begins to act strangely, culminating in her simply walking out and wandering around the town. The staff of the planetarium are bewildered, and one of the workers—a woman named Satomi Kurahashi—is ordered to go follow Yumemi and bring her back. Before long, Yumemi begins to run out of battery power.

Planetarian: Ultimate Edition features the 2016's 'planetarian HD' remaster, a kinetic novel based on a short light novel 'Snow Globe', four Drama CDs, and an art book.