In a world threatened by the Kiseichuu alien invasion and their devious plan to eradicate humanity by dampening their sexual desires, the HxEros device emerges as a potent weapon fueled by erotic energy. Fueled by his deep animosity towards the Kiseichuu, high schooler Retto Enjou teams up with a group of HxEros users to defend Earth. Together, they must harness their libido to power their gear and combat the alien threat. Surrounded by amorous girls in his home, Enjou finds himself in a constant wellspring of energy for the battle ahead.