Yumiko Yazawa works as the school nurse at Seisho Academy, attended by Daisuke Dojima and his friends. Students frequently call her by her first name due to her relatively young age, causing her noticeable discomfort and undermining her authority as an educator. She is present at the academy during the initial "Shibuya Drift" event, which transports part of Shibuya 300 years into the future. When earthquakes strike and Revisions attack, she is captured alongside students by a mechanical monster and confined within its bio-cage, a cryogenic containment unit. Daisuke rescues her after destroying the Revision in the subsequent battle.