Miyagawa Atsushi is an 11-year-old boy who is 180 centimeters tall. Since he has a grown-up looking build but acts his age, he has always been running into troubles. On the other hand, his 17-year-old elder sister Atsumi is only 137 centimeters tall. Even though she has a childish looking build, Atsumi takes good care of Atsushi.

Deijiko is the princess of the planet of Di Gi Charat. After reading a book, she is influenced to want to help everyone be happy. She leaves the castle and pretends to be a normal girl. She tries to make everyone happy by taking various jobs around the town and thereby making all sorts of new friends and inevitably, enemies.

Two planets, one to the East and another to the West, were once bound together by a chain called the Dragon Stream. But now, that chain is broken and the two halves are only joined in war. Nobunaga the Fool is heir to the Eastern Country of Owari. Regarded as too foolish and carefree by many, including his friends, Nobunaga is thought to be a nuisance even by his father. A girl from the West named Jeanne Kaguya d'Arc has visions of a "Savior-King." She is accompanied by Leonardo da Vinci as she journeys to the Eastern Planet in search of the person in her visions. Leonardo and Jeanne quickly fall victim to a military confrontation between powerful mecha, only to be saved by Nobunaga. Nobunaga takes control of Leonardo's mecha, intending to warn his family of the siege he suspects. Jeanne suspects that the lackadaisical Nobunaga might be the Savior-King she's envisioned.

Night Wizard. A term given to those whose mission is to protect the world from impending darkness. Renji Hiiragi is one such Night Wizard, who is constantly called on missions, even though all he wants is to be able to go to school and graduate. However, his latest order was to protect Elis Shiho, who is a new transfer student at his academy. Being dragged into the Astronomy Club by Renji's childhood friend, Kureha Akabane on her first day at school, Elis soon realises that she too, has the power to become a night wizard, after possessing one of seven secret Jewels, the Jewel of Kindness. Along with Renji and Kureha, Elis now begins her fight and her new life, as a Night Wizard