Charlotte Roux is a French girl who moves to the United States through a free-paid student transfer program to spend her freshman year at a magnet school in Chicago. Though this girl may seem ordinary she is far from it. Charlotte is a Demon Blood. When she was born a demon took over her body and she gained the power to host it. The rules state that she will be granted superhuman abilities and the ability to physically transform into the demon she hosts. However, when she dies her soul will reach a carnivorous end as it will be eaten by the demon. On her first day at school in Chicago, she notices the aura of a Demon Blood known as Vayle Nightwalker, who just so happens to host Satan. Vayle shows Charlotte a tea shop called Black Cat, which is a super low-key place for Demon Bloods to hang out.