Kodaka Hasegawa, a recently transferred student who has trouble making friends due to his scary appearance, encounters his classmate, Yozora Mikazuki, talking to an imaginary friend. As they both talk about their troubles in making friends, Yozora gets the idea to create a Neighbors Club dedicated to help people make friends. After Kodoka and Yozora post up recruitment posters, another student, Sena Kashiwazaki, comes to join, saying that, despite her popularity, she also wants to make some true friends, though she does not get along well with Yozora.

After Sena is caught playing an eroge and insists it's not perverted, Yozora has her read out the dialogue aloud to prove otherwise. Meanwhile, Kodaka's little sister, Kobato, feels jealous that Kodaka is spending more time with the Neighbors Club than with her. After encountering a swim-happy character in her game, Sena asks Kodaka to teach her how to swim. After the swimming lesson, Sena gets herself into trouble when she insults some guys hitting on her, forcing Kodaka to help her out. The incident reminds Kodaka of a friend he once had as a child, who taught him a lesson about friendship that Yozora strangely reacts to.