Mao Endou is known as "The Demoness" of her workplace; she's hyper-competent, strict, and ready to scold! However, she has a secret... she's dating the "angel" of the office, the kind and handsome Seiji Amatsuka! Seiji is the only one who knows that Mao isn't really the strict career woman she seems to be, and after dating in secret for half a year, the two are as in love as ever. But, there's just one small problem...