Sayaka was supposed to take an important exam today, but her stomach has been acting up, causing her to arrive late. Torn between the urgent need to use the toilet and the significance of the exam, she is suddenly struck by an unexpected incident. Meanwhile, office lady Aya also suffers from stomach troubles, yet is forced to go out due to an obligation with her boss. On her way back to the office, she discovers the toilets are occupied, and ends up defecating herself in the workplace. Sayaka, bound tightly by rope by a classmate, is completely immobilized. Overwhelmed by an intense urge to defecate, she finds herself in a creepy basement with no one coming to help. The exhaustion and humiliation following her involuntary bowel movement only deepen her torment.