Full of wonder and excitement, the Noah's Arc Circus troupe has captured audiences with their dazzling performances. Yet these fantastic acts do not come without a price. Children have mysteriously gone missing around London, correlating to that of the group's movements. Unsettled by these kidnappings, Queen Victoria sends in her notorious guard dog, Ciel Phantomhive; and his ever-faithful demon butler, Sebastian Michaelis, on an undercover mission to find these missing children. Trying to balance their new circus acts with their covert investigation under the big top, however, proves to be quite a challenge. With the other performers growing suspicious and the threat of the circus' mysterious benefactor looming overhead, what the two discover will shake Ciel to his very core.

Young Ciel Phantomhive is known as the Queen's Guard Dog, taking care of the many unsettling events that occur in Victorian England for Her Majesty. Aided by Sebastian Michaelis, his loyal butler with seemingly inhuman abilities, Ciel uses whatever means necessary to get the job done. But is there more to this black-clad butler than meets the eye? In Ciel's past lies a secret tragedy that enveloped him in perennial darkness—during one of his bleakest moments, he formed a contract with Sebastian, a demon, bargaining his soul in exchange for vengeance upon those who wronged him. Today, not only is Sebastian one hell of a butler, but he is also the perfect servant to carry out his master's orders—all the while anticipating the delicious meal he will eventually make of Ciel's soul. As the two work to unravel the mystery behind Ciel's chain of misfortunes, a bond forms between them that neither heaven nor hell can tear apart.

To the outside world, Hanabi Yasuraoka and Mugi Awaya are the perfect couple. But in reality, they just share the same secret pain: they are both in love with other people they cannot be with. Hanabi has loved her childhood friend and neighbor Narumi Kanai for as long as she can remember, so she is elated to discover that he is her new homeroom teacher. However, Narumi is soon noticed by the music teacher, Akane Minagawa, and a relationship begins to blossom between them, much to Hanabi's dismay. Mugi was tutored by Akane in middle school, and has been in love with her since then. Through a chance meeting in the hallway, he encounters Hanabi. As these two lonely souls spend more time together, they decide to use each other as a substitute for the one they truly love, sharing physical intimacy with one another in order to stave off their loneliness.

In the dawn of the 21st century, magic, long thought to be folklore and fairy tales, has become a systematized technology and is taught as a technical skill. In First High School, the institution for magicians, students are segregated into two groups based on their entrance exam scores: Blooms, those who receive high scores, are assigned to the First Course, while Weeds are reserve students assigned to the Second Course. Mahouka Koukou no Rettousei follows the siblings, Tatsuya and Miyuki Shiba, who are enrolled in First High School. Upon taking the exam, the prodigious Miyuki is placed in the First Course, while Tatsuya is relegated to the Second Course. Though his practical test scores and status as a Weed show him to be magically inept, he possesses extraordinary technical knowledge, physical combat capabilities, and unique magic techniques—making Tatsuya the irregular at a magical high school.