Fuutarou Uesugi, a highly intelligent high school student known for his exceptional academic achievements, leads a solitary existence with no friends. Compounded by the burden of family debts, he lives a modest life. However, Fuutarou's routine existence takes an unexpected turn when a new transfer student named Itsuki Nakano challenges him for his regular lunch seat. In a brief confrontation, Fuutarou manages to secure his place by criticizing Itsuki's eating habits, causing her to storm off in anger.
Yet, Fuutarou's regret swiftly sets in when he discovers that he has been offered a lucrative opportunity as a private tutor for a wealthy family's academically struggling daughters. To his surprise, the beneficiaries of his tutoring services are none other than Itsuki and her four identical siblings: the shy Miku, the cheerful Yotsuba, the mischievous Nino, and the mature Ichika.
Teaching these quintuplets proves to be a formidable challenge for Fuutarou as the girls have little interest in serious studying. Now, he must navigate the complexities of tutoring five beautiful yet idiosyncratic girls, each with their own unique personality and quirks.