"Bakunyū Maid Kari" centers on Kari, a young man who inherits a mansion from his late grandfather. Upon moving in, he discovers that the property comes with a unique condition: it is managed by a group of maids, each with exaggerated physical traits, particularly their bust sizes. The maids are bound by a contract to serve the mansion's owner, and Kari, as the new heir, becomes their master. The series explores the comedic and often chaotic interactions between Kari and the maids as he adjusts to his new role.

The maids, each with distinct personalities, include the diligent and serious head maid, the mischievous and playful second-in-command, and others who bring their own quirks to the household. Kari, initially overwhelmed by the situation, gradually learns to navigate the responsibilities and eccentricities of his new life. The narrative frequently incorporates slapstick humor, misunderstandings, and lighthearted situations arising from the maids' exaggerated devotion and Kari's attempts to maintain order.

Themes of duty, loyalty, and the dynamics of master-servant relationships are woven into the story, though the focus remains on comedic and fanservice-driven elements. The series does not delve deeply into dramatic or complex plotlines, instead prioritizing episodic scenarios that highlight the interactions between Kari and the maids. The tone is consistently light, with no significant overarching conflict or serious stakes, making it a straightforward, humor-focused series.