After finishing their "debut," Kate, Emilico and three other pairs who started with them begin a new life as adults.

In her house, Mei Onigami discovers a strange round creature that only says "chimi." Her sisters, Mutsumi and Hazuki, agree to let the being stay with them until its owner comes to claim it. However, as soon as one of them utters the word "hell," more creatures show up until there are 12 in total. The sisters think nothing of this until the critters create a portal that summons an envoy from Hell. Jabberwock the Eighth, a horned and fanged man covered in fur, has come to unleash a living hell on earth under orders from his boss. However, when living in the human realm proves to be challenging, the Onigami sisters allow him to stay with them. They also take in his "Chimimoryo spirits"—the round demons that preceded his arrival. Called Jigoku-san by the Onigami sisters, this messenger from Hell has a lot of work cut out for him if he wants to take over the world. But before that, he will have to survive the everyday hells of human life.

Following the conclusion of the large-scale coalition campaign, the entirety of China is in a state of economic recovery. The victor of the battle, the state of Qin, is no different. There, the political parties led by Ying Zheng and Buwei Lü continue their inner conflict. Having played the role of king in the coalition battle, Zheng has the trust of the people—but Lü is far from out of the fight. In 18 months, he plans to interrupt Zheng's coming-of-age ceremony. Meanwhile, a Zhao army numbering 20,000 troops has set out toward Qin. In the royal court, due to the lack of generals capable of responding to the incoming threat, Lü slyly suggests that Zheng take command. However, Cheng Jiao, Zheng's half-brother, volunteers instead. As they grew to trust each other during the coalition battle, Zheng now accepts Jiao as his replacement. However, the Zhao forces retreat a mere half-day after clashing with Jiao's army. With trouble quickly brewing in the shadows, the internal struggle of Qin is only complicated further. There are only two men Zheng feels he can rely on: Bi, a general who commands 30,000 men; and Xin, the leader of the Fei Xin force.

For the agent known as "Twilight," no order is too tall if it is for the sake of peace. Operating as Westalis' master spy, Twilight works tirelessly to prevent extremists from sparking a war with neighboring country Ostania. For his latest mission, he must investigate Ostanian politician Donovan Desmond by infiltrating his son's school: the prestigious Eden Academy. Thus, the agent faces the most difficult task of his career: get married, have a child, and play family. Twilight, or "Loid Forger," quickly adopts the unassuming orphan Anya to play the role of a six-year-old daughter and prospective Eden Academy student. For a wife, he comes across Yor Briar, an absent-minded office worker who needs a pretend partner of her own to impress her friends. However, Loid is not the only one with a hidden nature. Yor moonlights as the lethal assassin "Thorn Princess." For her, marrying Loid creates the perfect cover. Meanwhile, Anya is not the ordinary girl she appears to be; she is an esper, the product of secret experiments that allow her to read minds. Although she uncovers their true identities, Anya is thrilled that her new parents are cool secret agents! She would never tell them, of course. That would ruin the fun. Under the guise of "The Forgers," the spy, the assassin, and the esper must act as a family while carrying out their own agendas. Although these liars and misfits are only playing parts, they soon find that family is about far more than blood relations.