On the eve of an important Monday meeting, department chief Momoko Isshiki is working late with her subordinate Ohta to prepare documents. However, the necessary files cannot be found anywhere in the storage room. Just as they're struggling, the lights suddenly go out. A notice says "Power outage due to equipment inspection," but the door is electronically locked and won't open. All other employees have already gone home, and there's no way to charge their mobile phones. Trapped together in the storage room until Monday arrives, Momoko and Ohta are forced to endure the confined, dark, and suffocating space. As tension and unease fill the air, how will their relationship shift? What new emotions will emerge between them in this desperate situation?