A school-girl rescues an alien and as a reward she gets a small device that contains the body of a sexy woman. The device allows the user to bodyswap with the body stored inside it. While in that body, the user's unoccupied body is safely stored in the device. One day after she changes into the sexy body, she drops the device and a perverse boy finds it. He decides to use it to create mischief...

Note: The story where Ai-chan rescues the alien is not included in this translation. It is in the chapter before this one.