Planetarian HD He tells the story of the distant future, where humanity has practically died out. This happened after the failure of the space program for the colonization of other planets. The cities of people did not take root anywhere in the solar system, and mortally dangerous rain began to go on earth. The only means of survival for earthlings is digging in the garbage and the search for artifacts that are already ancient civilization for them.

Behind the plot of Planetarian HD, it is necessary to observe from the eyes of one of the junkers, people looking for useful things in ruins. Making his way through the next rubble, the guy climbs into the most dangerous of the famous places-the Sarkophage city. Exploring it, the protagonist enters the very center, where he discovers the preserved planetarium. And there he is unexpectedly met by the still functioning girl-robot Hoshino Yumemi.

Hoshino's function is to be a guide, and therefore she immediately decides that the main character is its first visitor in many decades. The protagonist agrees to help her in the repair of the projector and eventually spends with the girl for some time. The conversations of the characters are often allowed into philosophy, because the junior is a finished pessimist, and his new girlfriend is assimiled by optimism and naivety.

In terms of gameplay, the game is a kinetic novel. Its main difference from visual short stories is that the player will not have to make any elections. History is strictly linear, has no different endings and not change after the first passage. It only needs to be read by watching the arts and listening to music that is suitable under the atmosphere.