The film adapts and expands the Planetarian visual novel by Key. The story is set in a dystopian future where biological and nuclear warfare has left a once prosperous civilization in complete ruin. The film tells the story of an old man travelling around with a mobile planetarium projector to show people the stars.

The new OVA will feature the prequel short story "Snow Globe," which debuted as part of a light novel volume that bundled with a limited-edition version of the original PC game.