Nina is a plain and unassuming maid who serves the house of Count Mirkwood. Her life is turned upside down when she is suddenly dismissed for a crime she did not commit, accused of breaking her master's cherished vase. Cast out with nowhere to go, Nina decides to see this as an opportunity to explore the world beyond the mansion walls for the first time.

Despite her petite and humble appearance, Nina is no ordinary maid. She possesses superhuman talents and an incredible work ethic, having secretly handled almost all the chores in the mansion by herself because her master once instructed her not to stand out. On her journey, she quickly puts her skills to use helping new friends. She meets Emily, a rookie mage who possesses an abnormally large amount of magical power but cannot properly channel it. She also encounters Astrid, a brilliant but eccentric inventor whose experiments often fail to succeed. Using her absurdly over-competent skills, from cooking and cleaning to clearing blocked mana meridians with a massage, Nina finds a way to solve every problem she comes across.

The story takes place in a fantasy setting, following Nina as she travels from town to town in a mostly episodic fashion. As she helps those in need, she accumulates a small party of friends who recognize her incredible talents and vulnerability. Meanwhile, back at the estate of Count Mirkwood, things quickly become chaotic and messy in Nina's absence, suggesting that her former employer may soon regret his decision.

One notable narrative thread involves the characters she befriends, including a third companion named Tien, a hungry orphan from the Moon Wolf Tribe who has no strength. The story focuses on Nina's journey of self-discovery and the growing found family around her, all while her former household falls into disarray. The manga is a lighthearted power fantasy that celebrates competence, with hints that at least one character may have been reincarnated from modern Japan.