In a small fishing village, a gloomy middle school student named Kai meets a mermaid named Lu.

As a group of university students go out for a night on the town, a sophomore known only as "The Girl with Black Hair" experiences a series of surreal encounters with the local nightlife – all the while unaware of the romantic longings of "Senpai", a senior student who has been creating increasingly fantastic and contrived reasons to run into her in an effort to win her heart.