As the son of a long line of Onmyou mystics, 12-year-old Nakahito wishes to be a powerful mystic like his older brother, Kamihito. After being bullied by older boys into sneaking into the secret lab of Dr. Ayanokoji, Nakahito comes across a pink-haired woman in a maid's outfit. At first, Nakahito believes she is just a life-sized doll, but when she falls on him and their lips touch, she comes to life! Now this girl, Kurumi, is totally devoted to him, calls him "Master," and will gladly do anything he asks... if only he knew what to do with her.

Nakahito is a nervous and insecure child. He often feels bad for not being as great a mystic as his older brother. He is often embarrassed by the rapt attention Kurumi gives him. But, over time, his relationship with her grows.

(Source: animenfo.com)