Cast out of Heaven for defying its will, Lucifer falls to the depths of Hell, where the ruling Demon Lords seal her angelic power away. She takes up with Leviathan, a minor Demon Lord of Envy with ambitions of her own, and with Maria Totsuka, a human high school girl caught up in the fall, and sets out to win her power back one Demon Lord at a time. The manga plays its demon-versus-angel premise for ecchi comedy as the mismatched trio clash their way through Hell's ranks.