Kodaka Hasegawa, a transfer student with a delinquent appearance due to his blonde hair, struggles to make friends at St. Chronica's Academy. His life changes when he encounters Yozora Mikazuki, a loner who talks to her imaginary friend. Recognizing their shared social isolation, Yozora suggests forming a club to help others like them make friends. They establish the Neighbors Club, a group dedicated to fostering social connections among its members.

The club attracts a diverse group of individuals, each with their own quirks and challenges. Sena Kashiwazaki, a popular and beautiful girl, joins after overhearing Yozora and Kodaka's conversation. Despite her outward confidence, Sena struggles with genuine friendships due to her sheltered upbringing and reliance on her looks. Rika Shiguma, a science-obsessed classmate with a blunt and perverse sense of humor, also becomes a member, adding a layer of eccentricity to the group. Yukimura Kusunoki, a girl who dresses and behaves like a male servant due to her admiration for Kodaka, further complicates the dynamics with her loyalty and gender identity confusion.

As the Neighbors Club grows, the members engage in various activities, from playing games to hosting events, all aimed at improving their social skills. However, their interactions often devolve into comedic misunderstandings, romantic tension, and personal conflicts. Yozora and Sena, in particular, frequently clash due to their contrasting personalities and mutual jealousy over Kodaka's attention. Despite their differences, the group gradually forms a bond, learning to navigate their insecurities and misunderstandings.

The narrative explores themes of friendship, loneliness, and self-acceptance, as each character confronts their personal struggles. Kodaka, while serving as the central figure, often finds himself mediating between the strong personalities of the club members. The series balances humor with moments of introspection, highlighting the complexities of human relationships and the challenges of overcoming social barriers.

Throughout the series, the Neighbors Club's activities and interactions reveal the characters' growth and the deepening of their friendships. The story concludes with the group reflecting on their journey, acknowledging the progress they've made in understanding themselves and each other. While the ending leaves some relationships unresolved, it emphasizes the importance of the connections they've forged and the impact of their shared experiences.