The man she decided to marry has a history of divorce—and the reality of living together with his son from his previous marriage. Sharing a household with her stepson, who isn't much younger than her, he begins making unreasonable and lewd demands on his new wife, Yui. "If you're gonna be my stepmom, show me you've got the guts for it!" Yui is forced to confront this twisted and oppressive situation head-on.