Kasumi, living her married life with her beloved husband, has moved into their new home and is only thinking about a happy Mirai. One day, she ends up temporarily hiding her husband's younger brother (a worthless human being) Masaki. Naturally, Kasumi hates Masaki, but her husband tells her that he is her only surviving relative and she has no choice but to live with him. A few days later, when her husband goes on a business trip, Masaki takes over the house as if it were his own, and repeatedly behaves in a way that disgusts Kasumi. When Kasumi scolds him for this...