The story begins with Sora, a former Japanese high school student who died in a suicide attempt and was reborn as a young elf girl in a new world. She was captured by slave traders and purchased by Kisaragi Shuuya, a former Japanese high school student who died in a traffic accident and was reincarnated with cheat abilities. Shuuya, who has a fondness for elves, bought Sora despite her being disguised as a goblin-human half-breed. Sora, initially relieved to be bought by a fellow countryman, soon finds herself in a precarious situation. Shuuya, driven by his desires and his "cheat" abilities, reveals his intention to treat Sora as a sex slave. Sora, terrified, attempts to deter him by revealing she is biologically male, but Shuuya dismisses this, finding the idea of "corrupting" a boy into his ideal girl appealing.
Two weeks later, Sora is still recovering from Shuuya's advances. Shuuya is busy with typical "cheat protagonist" events, including obtaining identification and dealing with potential romantic flags. Sora, craving sweets, discovers Shuuya has a hidden basement with a refrigerator containing cupcakes. Her curiosity leads her to a hidden room behind a closet in Shuuya's bedroom. Inside, she finds a room filled with what appears to be torture and punishment equipment, causing her to flee in terror. Shuuya later explains the house was a former noble's villa where he imprisoned and tortured slaves, which is why it was cheap.
Shuuya returns from hunting a wyvern, having leveled up and acquired guild cards for himself and Sora. He also seems to have acquired a romantic flag with a tsundere mage girl. Sora, still recovering from Shuuya's actions, is given two "gacha" medals by Shuuya to try out a new skill acquisition system. Her pulls result in the "Charm" skill, which enhances positive emotions towards her, and "Angel's Kiss/Pretty Kiss," which heals with a kiss. Shuuya, meanwhile, obtains a powerful sword, "Levantine," and the "Talented Swordsman" and "Lustful Man" skills.
Sora, overwhelmed by Shuuya's relentless advances and the "Lustful Man" skill, decides to propose a solution: Shuuya should buy a new slave. Shuuya, though initially hesitant, agrees. He returns with a new slave, a 15-year-old cat-eared girl named Ruru. Ruru, initially intimidated by Sora, quickly becomes competitive, believing she can secure a privileged position by pleasing Shuuya. Sora, however, sees Ruru as a potential ally and a way to lessen her own burden. Ruru, after experiencing Shuuya's intensity firsthand, is saved by Sora's intervention, leading to a shift in their relationship. Ruru becomes more of a supportive junior, and together they manage to reduce Sora's workload.
The group embarks on a journey to deliver a merchant. During the trip, they are ambushed by bandits. Shuuya easily defeats them, showcasing his power. Ruru, initially seeming like a typical cat-eared slave, reveals a surprisingly strong combat ability and a somewhat manipulative, "black-hearted" personality. She also seems to be developing a rivalry with the female adventurers they encounter, Rebecca and Clarice, who are also developing feelings for Shuuya.
Later, while exploring a dungeon, Sora and Ruru encounter Cain, a young adventurer who sold his childhood friend into slavery to pay off his debts. Shuuya recognizes Cain as a troublesome individual. Sora and Ruru are deeply disturbed by the situation, highlighting the harsh realities of their world.
The group continues their dungeon exploration, with Shuuya effortlessly clearing floors. Sora, despite her desire for combat, is largely relegated to support roles due to her limited magic and physical strength. They encounter a centaur-like monster and a dragon skeleton, both of which Shuuya defeats with overwhelming power. Sora, frustrated by her lack of progress and the constant threat of Shuuya's desires, expresses her boredom and lack of physical activity. Shuuya, in response, carries her to his bedroom, implying an "punishment."
After returning from the dungeon, Sora is suffering from muscle pain. Shuuya is unusually gentle, which Sora finds suspicious. She also develops a strange aversion to horses. They then move on to a new dungeon, the "Underground Bell Tower Dungeon." During their exploration, they encounter Cain again, who is now accompanied by two female adventurers. Cain, despite having sold his childhood friend, criticizes Shuuya for having slaves. Shuuya dismisses his criticism, and the encounter ends with Sora losing consciousness.
Upon waking, Sora learns that Shuuya had to deal with Cain, who apparently fled due to Sora's condition. They return to their town, Petesh. Clarice, the mage, has moved on from Shuuya after being thoroughly rejected. Sora and Ruru then encounter a merchant being extorted by adventurers, and Ruru, in a display of her manipulative nature, incites Clarice's jealousy towards Sora. Clarice, having found a new love interest, recounts her obsessive pursuit of him.
The story concludes with Shuuya, Sora, and Ruru returning to their home. Shuuya's "punishment" for Sora is implied to be a gentle one, but he warns her that the real punishment awaits them back home. The narrative emphasizes the contrast between Sora's male inner self and her current female elven body, and the constant threat of Shuuya's desires.