"Girlfriend, Girlfriend" centers around Naoya Mukai, a high school student who begins dating his childhood friend Saki Saki after she confesses her feelings for him. Their relationship takes an unexpected turn when Nagisa Minase, another classmate, also confesses her love for Naoya. Instead of rejecting Nagisa, Naoya proposes the unconventional idea of dating both Saki and Nagisa simultaneously, believing he can love and care for both equally. Saki, though initially resistant, reluctantly agrees to the arrangement, leading to a chaotic and comedic dynamic as the three navigate their unconventional relationship.

The series explores the challenges and misunderstandings that arise from this polyamorous setup. Saki struggles with jealousy and insecurity, often clashing with Nagisa, who is more easygoing and earnest in her affection for Naoya. Naoya, while well-meaning, frequently finds himself caught between the two girls, attempting to balance their conflicting personalities and emotions. The trio’s relationship is further complicated by the introduction of additional characters, such as Rika Hoshizaki, a childhood friend of Naoya who harbors her own feelings for him, and Shino Kiryuu, Saki’s best friend, who becomes entangled in the group’s romantic entanglements.

The narrative thrives on comedic misunderstandings, exaggerated reactions, and over-the-top scenarios, often highlighting the absurdity of the situation. Despite the humor, the series occasionally delves into the emotional complexities of love, trust, and communication, as the characters grapple with their feelings and the societal norms surrounding relationships. The story progresses through a series of episodic conflicts and resolutions, with each character’s development contributing to the evolving dynamics of the group.

"Girlfriend, Girlfriend" blends romantic comedy with situational humor, focusing on the interactions and growth of its central characters. The series maintains a lighthearted tone while occasionally addressing deeper themes of love and commitment, making it a distinctive addition to the romantic comedy genre.