Kokoro, a high school girl who is about to take the entrance exam, is often molested on the morning school bus! It always happens before her period, when her body starts to become sensitive... Kokoro has no choice but to endure it. She is scared and can't make a sound, and at the same time, she endures the shame that she feels from the man's fingertips! Before she knows it, the molestation escalates more and more boldly!