A fourth-grader, Aoyama-kun, investigates the mysterious reason behind the sudden appearance of penguins in his village, which is somehow related to a power from a young woman working at a dental clinic.

The story of the titular girl known only as "Otome" and her insanely long night of partying and drinking-complete with a book fair, festival, and many adventures in between. It is also the story of "Senpai," her upper class man who has been...