Yuuya, a NEET, is tasked with caring for his nieces, Misaki and Sasa, as their live-in housekeeper. A comical mishap occurs when he accidentally puts on adult panties he finds while doing laundry to 'understand the twins better.' When he greets the twins wearing them, chaos ensues. In another escapade, Yuuya takes the twins to the beach, where Sasa has unconventional plans. Later, when the twins invite friends over, Yuuya's dinner plans are disrupted by a game of 'king.' Meanwhile, Takamiya nervously meets his girlfriend's family, bonding with her sister Honoka, who has more than sibling affection in mind. Lastly, a teacher faces temptation from his student and gravure idol, Kirishima, testing the limits of their illicit relationship.