Carrera is a female demon tasked with forging wish-granting contracts with humans in exchange for their souls. Together with her partners and rivals, Mercedes and Rati, she performs this duty for the benefit of the demon world. When the nerdy Ogawa summons Carrera, she finds him more intriguing than her previous clients and develops a crush on him. Mercedes also attempts to involve herself with Ogawa to compete with Carrera. However, female angels are disturbed by this interference and are prepared to purify the demons with their precious "holy water" to save Ogawa's soul.