Junko is nearly 30, nearing the traditional 'best before' of the Japanese society, and feels increasing pressure: without a partner candidate or even a particular wish to have children anytime soon, she decides to become an egg donor. And not just for the free Hawaii trip that would be the prize if her candidacy is successful. At a counseling session, she meets her niece Aki who has similar plans. Together, they soon see how competitive social and evolutionary rules can mess up the best human relationships, particularly when such rules are mixed with the fossilized attitudes of a society which is frantically hanging on to traditions.