Five years ago, alien beings known as the "Kiseichuu" invaded the world. With the species endangered, the Kiseichuu are determined to take over Earth through a deadly plan that would gradually wipe out the human race: take away humanity's sexual drive using various methods, allowing them to die out. In response to the Kiseichuus' scheme, the HxEros device was developed—a powerful weapon that only those with high levels of erotic energy can utilize Retto Enjou, a high schooler with a deep hate for the Kiseichuu, joins a gang of HxEros users to combat them and preserve humanity. With their gear depending on sexual energy for power, the team must work together to maintain high levels of libido.