Sou Kagura is enjoying his life as a new high school student until one day when his parents abandon him due to a large debt they had amassed. To get rid of their debt, they essentially sell him to Mikoto Ouzuki, a wealthy land developer who wants Sou as his sexual pet. However, Sou's older sister Ui intervenes with a proposal: If Sou can pay back the debt in one year, he's off the hook, to which Ouzuki agrees. What Sou only finds out later on is that Ui's plan is to open up a maid cafe with him as one of the maids under the name "Kanade."
(Source: MU)