Takaomi Kamikiza, a 15-year-old boy, lives in a mansion with Ami, his adorable 7-year-old sister; Hirofumi, his carefree 29-year-old brother; and Akira, their 19-year-old butler. After returning home one day, Takaomi is unexpectedly greeted by none other than his classmate Sara Kimishima—wearing a maid uniform!

As it turns out, Hirofumi hired her not only to take care of the housework, but also to satiate his obsession with maids. Initially, Sara's new presence in the household would make Takaomi flustered at times. But, as they become a part of each other's daily lives, their bond grows ever stronger and their relationship slowly passes the point of simply being classmates.