Harukaze Doremi considers herself to be the unluckiest girl in the world. Her parents are always fighting, her little sister makes fun of her, and her crush pines after another girl. If only Doremi could just wave a magic wand, she would have a much better life—or so she used to think. After a mishap with a real witch, Doremi becomes an apprentice witch herself, and it turns out she's pretty horrible at that, too. Now she and her two friends must study to become better at magic so they can become good witches. That is, if they can focus on their magic studies! The three apprentices will need all the luck they can get if they want to pass the witch exams and become full-fledged witches. Only then will Doremi's debt to the witch Majorika be repaid. Until then, Doremi will remain a useless little witch girl!

In the northern Kanto area in Japan, there is Binan City… At Binan High School, as per usual, the “Earth Defense Club (lol)” was a club that did nothing. The club members Kyoutarou Shuzenji, Ryouma Kirishima, Nanao Wakura, Taishi Manza, and Ichiro Dogou nonchalantly enjoyed tea while having pointless conversations that amount to nothing. All of them have now gathered at Kurotama Bath after school. When Ryouma pulls Kyoutarou Shuzenji by his arm out of water that he claims feels too good, together with his towel comes a pretty boy in strange clothing. These five boys are then dragged into a battle for the heir of the magical kingdom, Honila Land...

The older boys are graduating school and recount their memories together. The next day everyone defends the graduation ceremony against Zundar and Dadacha's Second Button Monster but Yumoto struggles using his love power.

In the kingdom of Earlshide, Merlin Walford was once regarded as a national hero, hailed for both his power and achievements. Preferring a quiet life however, he secludes himself deep in the rural woods, dedicating his time to raising an orphan that he saved. This orphan is Shin, a normal salaryman in modern-day Japan who was reincarnated into Merlin's world while still retaining his past memories. As the years pass, Shin displays unparalleled talent in both magic casting and martial arts, much to Merlin's constant amazement. On his 15th birthday however, it becomes apparent that Shin only developed his combat skills and nothing else, leaving him with blatant social awkwardness, a lack of common sense, and a middling sense of responsibility. As a result, Shin enrolls in the kingdom's Magic Academy to hone his skills and mature among other teenagers. However, living a normal life is impossible, as he is established as a local celebrity almost as soon as he arrives. Kenja no Mago follows Shin Walford's high school life in the capital as he makes new friends, learns about the world, and fights off the various forces of evil surrounding him and his city.