Yuuki wakes up to find herself in an unfamiliar manor, wearing a maid uniform and lying on a luxurious bed. Soon, she discovers five more girls, all dressed the same as her. This is the Ghost House, and the only way they can survive is to make it through the traps that lie in wait—deadly games full of blowguns, buzz saws, locked rooms, and weapons. It's a hopeless, terrifying situation for everyone there...well, everyone except Yuuki. After all, this is her career at seventeen. Do you think that's odd? She would agree. But that's how some people are—they earn their living playing death games. (Source: Yen Press)

For as long as the locals can remember, the Champignon Witch, Luna, has lived hidden in her cottage on the outskirts of the kingdom, deep within the Black Forest. Despite her occasional trips into town to deliver medicine, no one dares to come close to her as poisonous mushrooms grow everywhere she goes. Furthermore, as a black witch, Luna must lay low to avoid execution, as the kingdom only acknowledges and accepts white witches. Luna's lonely life turns around when she saves a dying boy named Lize. Upon learning that Lize is destined to become The End of All Things, Luna offers to become his teacher and stray him away from the path of evil. She must overcome her inexperience and create a great magician out of Lize to avoid his execution.

Demon King Ahriman has a problem: his daughter, Doux, loves everyone! Consequently, Ahriman had to halt his invasion of the world in the worry that his daughter's behavior is not one befitting someone of her kind. She loves making friends, helping others, and bringing happiness to all creatures including their enemies, the humans. Ahriman, however, congratulates Doux for her good deeds instead of scolding her. With the help of his aide Jahi, who is assigned as Doux's master, the two try to get rid of her kindhearted nature—so that the Demon King's daughter goes from a cute, adorable, and nice little girl to an inhuman, cruel, and twisted little demon.

To most people around Mizuki Ashiya, her sudden choice to move to Japan from the United States comes as a shock. Her sole reason for the transfer is to attend the same high school as her idol Izumi Sano, who stole her heart after she saw him compete in a high jump competition. However, there is one problem—Sano attends an all-boys school! That does not stop Mizuki, though, as she is committed to getting close to Sano by changing her appearance and demeanor. Mizuki luckily ends up in the same class and dormitory room as Sano, but her ideal plan is shattered when she finds out that he has quit high jump. Nevertheless, Mizuki is determined to learn more about him and rekindle his love for the sport, all while navigating her new life in high school and keeping her true gender hidden.