"Ogami-san Can't Keep It In" is a romantic comedy manga that centers on the dynamic between two high school students, Momo Ogami and Ryuichi Kijima. Momo Ogami is a reserved and stoic girl who struggles to express her emotions openly, often bottling up her feelings. Despite her outward coldness, she harbors a deep affection for Ryuichi Kijima, her childhood friend and classmate. Ryuichi, on the other hand, is cheerful, outgoing, and somewhat oblivious to Momo's feelings, though he cares deeply for her in return.

The narrative explores the humorous and often awkward situations that arise as Momo attempts to convey her emotions to Ryuichi. Her inability to express herself directly leads to misunderstandings and comedic moments, particularly as Ryuichi misinterprets her actions. Momo’s internal monologues reveal her frustration and longing, contrasting sharply with her outward demeanor. The story progresses through a series of episodic encounters, with each chapter highlighting the growing tension and affection between the two characters.

Supporting characters, such as classmates and friends, occasionally contribute to the comedic and romantic developments, adding layers to the central relationship. The manga balances lighthearted humor with moments of genuine emotional vulnerability, as Momo gradually learns to open up and Ryuichi begins to recognize her true feelings. The interplay between the characters’ personalities drives the narrative, creating a blend of comedy and romance that appeals to fans of the genre. The series maintains a focus on the evolving relationship between Momo and Ryuichi, with their interactions serving as the core of the story.