The Prince Became a Slave?!. Keiki, whose weakness was held by his junior Yuika, became her slave and spent his days being chased by unreasonable demands. If she has Cinderella's panties stolen from Keiki's room, she can put an end to her unhappy days... One day, Keiki gets a chance. Yuika disappeared in her bathroom, and when Keiki reached out her hand to the dresser, Yuika's scream reached her. Keiki rushes over and inadvertently sees Yuika naked, making her situation even worse. After that, Keiki is released from slavery with Yuika due to a coincidence, but after that, from a photo he saw at the astronomy club, Keiki arrives at a certain truth...!