42-year-old Kyoko Otsuka has spent the last 13 years living life as "mom" for her rebellious daughter and soft-spoken husband. Kyoko thought her average and hectic life would continue this way until one day she is told that she only has a year left to live! Shocked by this news, Kyoko decides she wants to spend the remainder of her life "living for herself." She declares to her family, who have been spoiled and taken her for granted, that she is done being their "mom" and is going to take back her life as "Kyoko"!

Iroha has stayed single all 23 years of her life. Her mother, who single-handedly raised her and gave her the life she has, has arranged a marriage interview. As a dutiful daughter, she agrees to attend. But before her life as she knows it is changed completely, she secretly plans out a final act of defiance. For her plan to be realized, she needs an accomplice. And thus, she makes a proposition to Kashiwagi, the best-looking guy at her workplace. Met with blunt refusal, Iroha initially becomes dejected. Then... not a moment too soon, Kashiwagi changes his mind and ends up agreeing to her plan. His request in exchange? To enter a contract relationship with him and become his "girlfriend" for the time being!