"Kawaikereba Hentai demo Suki ni Natte Kuremasuka?" centers around Keiki Kiryuu, a high school student who finds himself entangled in a series of romantic and comedic misadventures after discovering a love letter from an anonymous admirer. The letter, signed only as "your secret admirer, a pervert," sets the stage for Keiki's quest to uncover the sender's identity. The story explores themes of love, friendship, and self-discovery, framed within a harem-style narrative.

Keiki's investigation leads him to consider several potential candidates among his female acquaintances. These include Yuika Koga, a popular and seemingly perfect classmate; Mao Nanjou, a reserved and mysterious girl with a penchant for writing erotic novels; Sayuki Tokihara, the student council president with a bold and assertive personality; and Mizuha Kiryuu, Keiki's adoptive sister, who harbors complex feelings for him. Each character brings unique dynamics to the story, with their interactions often veering into comedic and lighthearted territory despite the underlying romantic tension.

As Keiki navigates his relationships with these girls, he encounters various challenges and misunderstandings, often stemming from their contrasting personalities and hidden quirks. The narrative balances humor with moments of introspection, as Keiki grapples with his own feelings and the moral dilemmas posed by his situation. The series also delves into the characters' backstories, providing depth to their motivations and behaviors.

The plot progresses through a series of episodic arcs, each focusing on Keiki's interactions with one or more of the central characters. These arcs build toward the overarching mystery of the love letter's sender, while also exploring themes of acceptance and the complexities of human relationships. The story maintains a lighthearted tone, with occasional forays into more serious and emotional territory, creating a blend of comedy, romance, and drama.

Throughout the series, the characters' growth and evolving relationships are central to the narrative. Keiki's journey is marked by his efforts to understand the feelings of those around him while confronting his own insecurities and desires. The series concludes with resolutions to the central romantic conflicts, offering closure to the characters' arcs while leaving room for interpretation regarding their future paths.