Wealthy, handsome, and successful, Arthur Louis Zetes is no stranger to the greed of people. Constantly doubting those around him, he has no faith in humanity; thus, he makes a request for the perfect maid—a robot maid. However, his butler is unable to acquire such a servant due to technological limitations, so he finds the next best substitute. Marie Evans is a former child prodigy in martial arts known for her lack of expression. Drowning in debt, she readily accepts the offer to be a maid that acts like a robot. While Arthur is often blunt towards humans, he cannot help but dote on his personal robot; in turn, Marie is moved by his drive and consideration toward her.

Yuuken "Yuu" Enma is an average Japanese high school student preparing for an upcoming kendo tournament. On the night before the competition, however, a black carriage crashes into him. When he regains consciousness, Yuu finds himself at Night Raven College—a premier academic institution in the magical world of Twisted Wonderland. Only a chosen few with exceptional magical talent are admitted into the school, so it is a mystery how a human with no magic ability ended up here. Although Yuu desires to return home, it is easier said than done. While the school's headmaster searches for a way to send him back, Yuu is assigned manual labor around the campus. But due to the chaos at the school's entrance ceremony following his arrival, Yuu has a target painted on his back as far as Heartslabyul dorm leader Riddle Rosehearts is concerned. Yuu meets and befriends Heartslabyul freshmen Ace Trappola and Deuce Spade; yet soon after, Ace and Deuce land in a situation that results in their expulsion. As the pair seek to redeem themselves, Yuu accompanies them on their perilous mission to fix school property. However, forgiveness does not come easily from the "Crimson Tyrant" in charge of Heartslabyul, who may have an ulterior motive behind his strictness.

After her parents were brutally murdered, school girl Sawa was taken into custody by Akai and Kanie, a pair of detectives assigned to her case. Corrupt and immoral, they train the girl to become a weapon, dangling the promise of vengeance in front of the hapless orphan. From celebrities and politicians to influential businessmen, Sawa is tasked with assassinating targets selected arbitrarily by her crooked overseers. She executes every mission without fail, and her distinctive weapon has become infamous among the city's police officers. Physically abused by Akai, who is no more righteous than her victims, Sawa begins to dream of a life unhindered by the shadow of her "guardians." One day, Sawa meets Oburi, a fellow orphan and vigilante. They quickly form a bond born of desperation and disgruntlement at the unjust world, envisioning a future free from the stain of murder.

Kiki, a 13-year-old witch-in-training, must spend a year living on her own in a distant town in order to become a full-fledged witch. Leaving her family and friends, Kiki undertakes this tradition when she flies out into the open world atop her broomstick with her black cat Jiji.

As she settles down in the coastal town of Koriko, Kiki struggles to adapt and ends up wandering the streets with no place to stay—until she encounters Osono, who offers Kiki boarding in exchange for making deliveries for her small bakery. Before long, Kiki decides to open her own courier service by broomstick, beginning her journey to independence. In attempting to find her place among the townsfolk, Kiki brings with her exciting new experiences and comes to understand the true meaning of responsibility.