An adaptation of the visual-novel by Key, Planetarian: Hoshi no Hito combines the story of the original work with an expansion that extends the narrative with content from the Hoshi no Hito light-novel sequel. In the future after much of the world has been devastated by nuclear and biological warfare, a young scavenger or "Junker" exploring a quarantined and abandoned city comes across a service robot still faithfully awaiting customers in the rooftop planetarium of a department store. Against his pragmatic instincts he helps the robot repair the planetarium's projector: a decision which will change both their fates.

Based on a 1984 serial on the "Animevision" video magazine. The original material was compiled into this one-shot video.

Momoko, who attends a special school, is both mentally and physically disabled. Every morning she becomes peevish because she can't go to the ordinary school with her twin brother Riki. Her family soothes Momoko by singing her favorite song "The Song of Frogs." One day, Momoko shouts encouragement to Riki who's playing dodgeball at an open classroom day and Riki's team wins the game. Ryuji, whose team lost the game, is not impressed and demands that Riki stop bringing his 'idiot sister' to school. Riki totally loses control and hits Ryuji with all his might. The following year, an experiment in integrated education is implemented and Momoko begins to attend Riki's school. Unfortunately, her physical condition takes a turn for the worse and she's sent to a hospital. Riki and all her classmates want to cheer her up and they set a goal of winning a relay race so that they would be able to tell Momoko the good news. Meanwhile, the fastest sprinter, Ryuichi, insists that he won't be taking part in the race.

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.