"LDK" is a romantic comedy manga series that centers on the evolving relationship between Aoi Nishimori and Shusei Kugayama, two high school students who become unlikely roommates. Aoi, a diligent and responsible student, lives alone in an apartment provided by her father. Her life takes an unexpected turn when Shusei, the most popular and handsome boy in school, moves in next door. After a fire destroys Shusei's apartment, Aoi reluctantly agrees to let him stay with her temporarily, setting the stage for a series of comedic and heartfelt interactions.

The narrative explores the dynamics of their cohabitation, highlighting their contrasting personalities. Aoi is pragmatic and reserved, while Shusei is confident and flirtatious. Despite their differences, they gradually develop a deeper connection, navigating misunderstandings, jealousy, and external challenges. The story delves into themes of trust, vulnerability, and personal growth as both characters confront their feelings for each other.

Secondary characters, such as Aoi's childhood friend Riku and Shusei's admirers, add complexity to the plot, creating tension and complicating the central relationship. The series balances lighthearted humor with moments of emotional depth, capturing the awkwardness and intensity of young love. Over time, Aoi and Shusei's bond strengthens, leading to a gradual progression from reluctant roommates to a genuine romantic partnership. The manga concludes with a resolution that underscores their growth as individuals and as a couple, offering a satisfying conclusion to their journey.