Iroha had a child named Masaki through an affair and lived a tough life as a single mother. Striving as a career woman, she worked hard to provide Masaki with a better environment. Though Masaki never complained, he felt lonely seeing his mother rarely take time off. When Masaki turned twenty, Iroha suggested, "Take some paid leave once in a while." That became the opportunity for them to visit an onsen inn together. However, Iroha remained preoccupied with work matters and failed to truly cherish the time spent with her son.