Following the revelations of the archangel Gabriel, Ente Isla hero Emilia Justina—who lives on Earth under the alias Emi Yusa—starts doubting the validity of her mission to slay the Demon Lord Satan, now reduced to a modest employee of MgRonald's as Sadao Maou. At the same time, Sadao's high school-aged coworker Chiho Sasaki pursues a new dream with hopes to protect not only herself but also her friends. Secretly training with Emi and Suzuno Kamazuki to develop telepathic powers, Chiho's training is cut short when a group of demons abducts her. As angel and demon attacks threaten the fragile peace between the two worlds, Sadao and Emi need to put their troubled past behind them if they want to have a chance to find their new purpose in life.

A decade ago, mankind witnessed the deadly potential of weapons caused by the Great War. To avoid another catastrophe, governments worldwide have resorted to espionage to fulfill their agendas. In the Din Republic, Lily is an enthusiastic young girl who aspires to become a spy and serve her nation. However, she begins to doubt her abilities, as she struggles to perform well academically. Lily's passion is reignited when she is offered provisional graduation by joining the spy team Lamplight, which she eagerly accepts despite the enigmatic nature of the opportunity. Upon arriving at her destination, Lily is surprised to find six other girls waiting there, all of whom have faced their own academic difficulties as well. A mysterious man named Klaus soon appears and reveals they must complete an Impossible Mission: to infiltrate the Galgad Empire after just one month of training. Although skeptical, the girls eventually agree to work together under Klaus' guidance—as this might be their only chance to prove their worth as spies.

Being the daughter of a modeling agency owner, Chiyuki Fujito aspires to represent her father's agency in the prestigious Paris Fashion Week, shining under the spotlight as a runway model. However, although she is equipped with great looks and talent, she unfortunately lacks a key element in becoming a successful model—height. Stuck at 158 cm even after entering high school, her childhood dream seems out of reach. Meanwhile, Ikuto Tsumura is a high school student with a knack in designing clothes; however, without the resources to pursue the necessary education, his ambition of becoming a fashion designer remains a mere dream. But as fate brings Chiyuki and Ikuto together, the dim hopes within their hearts are ignited once again. Together, the two promise to rebel against convention and carve out their own paths in the fashion world.

Lucifer, an Archangel and former head of the Seven Heavenly Virtues, is banished from Heaven after revolting against the Lord's will. While plummeting from the skies, she is halted halfway between Heaven and Hell after crashing through the roof of a high school church. Though she is witnessed by Maria Totsuka, a soft-spoken student at the academy, Lucifer swiftly continues her descent into the depths of Hell. Soon after her arrival, Lucifer is found by aspiring Demon Lord and fangirl Leviathan. The two decide to overthrow the Seven Sins, the authorities of Hell under the leadership of Belial. But with their combined powers, the Seven Sins are able to repel Lucifer and contain her divine powers by placing a Garb of Punishment over her body, transforming Lucifer into a Demon Lord. Longing for revenge and accompanied by Leviathan, Lucifer makes her way back to Earth, where she forces Maria to become her immortal slave. Together with her new accomplices, Lucifer sets out on a mission to subdue the Seven Sins so she may be free of the curse brought upon by her Garb.