Yuji, a hardworking husband, finds his marriage strained due to their busy daily lives. One day, after a minor argument, his wife returns to her parents' home. At the suggestion of his in-laws, Yuji begins living with his mother-in-law and father-in-law. The confined living space increases his stress, leaving him mentally and physically overwhelmed. One day, he accidentally witnesses his in-laws engaged in an intimate moment. Seeing his mother-in-law's bold behavior ignites an intense arousal unlike anything he's ever felt with his wife. The next day, the mother-in-law confronts him, saying, "You were watching me yesterday, weren't you?" Shaking Yuji to his core.