Ichiko is a care-giver and a nurse. She provide home-care to the Oishos' elderly woman and is almost considered part of the family as she visits and performs her tasks routinely. What is more, Ichiko is helping Oisho Motoko to also become a care-giver and potentially replace her one day. The two have become close, which is useful when Motoko's sister Saki disappears. She is returned safely one week later, but the kidnapper is too close to home.