The hero and his party have reached the threshold of the Demon Lord's castle, only to discover that the final door leading to their enemy cannot be opened by a virgin. This absurd rule forces the unprepared hero, accompanied by the party's three female members, to retreat and devise a new strategy: he must lose his virginity before he can complete his quest.

The party consists of the hero himself, the mage Sarisa, the saint Nakoti, and the thief Garuko. When the hero awkwardly asks one of them to help him, they harshly refuse, and a status check reveals that their affection for him is supposedly zero while his feelings for them are merely average. The group agrees that he cannot be expected to act out of a sense of duty, so they decide his mission is to raise one of the women's affection for him to one hundred before he can proceed.

What the hero does not know is that the displayed affection scores are a lie. In reality, all three women already have maximum affection for him, and he secretly harbors maximum affection for each of them as well. However, each heroine has personal reasons for hiding her true feelings. The long-lived elf Sarisa has become a twisted tsundere due to her inexperience with love. Nakoti, as a holy woman, feels compelled to suppress her desires. Garuko is bound by the laws of her beastman tribe that prevent her from taking the hero as a mate. All three secretly wish to be loved for genuine romantic feelings rather than out of a sense of mission.

The hero, despite his true affection, often behaves insensitively out of embarrassment. Thus the manga follows the four characters as they engage in a comedic battle of wits, each trying to raise the others supposed affection score without revealing their own true feelings. Their attempts repeatedly backfire, involving failed strategies such as love potions and hypnosis, leading to a series of misunderstandings and increasingly convoluted schemes.