Yuriko raised her son, born when she was a university student, and worked as a teacher while living independently. On a long-awaited hot spring trip with her son, she felt joy at his growth but also inner turmoil about her own life. In the warm outdoor bath, her son removed his blouse and skirt, gazing at his mother lying beside him in her underwear. Her sensual figure stirred his desire, arousing him gradually. Yuriko, wishing to still be cherished as a woman, found herself overwhelmed by forbidden emotions. In a quiet, traditional inn, an illicit bond slowly deepened between mother and son.