In Planetarian, you are known as the "Junker" in a post-apocalyptic world. Trying to survive on your own in this always-raining world from robots like giant "fiddler crabs" that shoot lasers. One day, he enters a rundown building which apparently is a planetarium. Surprisingly to himself, there was an active android there (which he was about to shoot.) She called herself Yumemi (but I remember it as Reverie, but it doesn't matter anymore.) And that's when there's odd story unfolded.