Sakura became pregnant at the age of 20 and gave birth to Tatsuya on her own. After graduating from high school, Tatsuya entered nursing school and began pursuing a career as a nurse. One night, shortly before Tatsuya was set to enter nursing school, Sakura awoke to the sensation of someone touching her body. Recognizing the touch as Tatsuya's, she pretended to remain asleep. Later, after Tatsuya graduated from nursing school and received his first vacation, he returned home. Wanting to spend some long-awaited time alone together as mother and son, Sakura invited Tatsuya on a hot spring trip.