Based on 16-year-old writer Sarie Hinakura’s award winning story Jellyfish is centered around two adolescent girls disconnected from their immediate environment of school and mates. They first get together while staring into a jellyfish tank at a local aquarium. The relationship that ensues eventually faces tension from the divergent personalities of the two protagonists, one of whom explores a heterosexual relationship with a fellow student. Jealousy and the wrath of a lover spurned are inevitable spillovers.

Second year high school student Kodaka Hasegawa has transferred to his new school about a month ago, but he still hasn't made any friends. Kodaka Hasegawa was born from a Japanese father and a British mother. Because of his appearance, people think Kodaka Hasegawa is a troubled kid. One day, Kodaka Hasegawa sees classmate Yozora Mikazuki pleasantly talking to herself. Kodaka Hasegawa talks with her about how to make friends. To make friends, Yozora Mikazuki decides to form the Neighbor's Club and forces Kodaka to enroll in the club.