Yumi Nagoshi is one of Rei Kisaragi's cronies in high school. One day, she was on a field trip on a ship, however, the ship that was used got hit by a storm and the lifeboats were capsized. Miraculously, she drifted toward an island.

She sits in bed next to you in a building. She looks at you, shyly. "Uhm, we should huddle for warmth...~"