Twins Yuko and Keiko lost their parents in the Sea of Japan crash that killed 138 passengers and crew. Her older sister, Yuko, who became an adult over time, developed a deep relationship with Akio Tashiro, who behaved badly, despite the concerns of her surroundings. However, Yuko doesn't tell Akio about her sister's existence. There was a plot behind it, and a sad reason...
