The children's anime revolves around Velonica, a high-handed and ultra-selfish little alien girl on the Galaxy Network, who begins to cause havoc on Earth. After a "fated encounter" with an Earthling boy, Velonica wavers between a possible budding romance with the boy and her dedication to the arts.

Confined in the castle tower by her father, princess Arete spends her days watching the world outside her window. Sometimes she seeks out to watch the common people at work. The knights of the kingdom compete for the right to marry her and rule the land by competing to see who can find powerful magic objects made by a long dead race of sorcerers. Arete wants none of this. She longs to meet the common people and travel to exotic lands she has only seen in the books she keeps hidden under her bed. One day the sorcerer Boax arrives in a fantastic flying machine and offers to take Arete as his wife and transform her into a proper princess.

Due to her father's remarriage, robust 16-year-old Himeno Awayuki moves into a large mansion with a beautiful garden—the quintessential dream house for any girl her age. However, much to Himeno's disappointment, her new stepfamily doesn't really seem to like her, as her stepmother often occupies herself with her father, her younger stepsister Mawata ignores her, and her other stepsister—the equally aged Mayune—tries to prank her at every opportunity. But Himeno doesn't have time to dwell into thoughts of hopelessness—her new life has now become involved with a group of seven magical boys known as the Leafe Knights, after they ask her to become a magical princess who can borrow their powers! Although Himeno accepts their request and becomes the Prétear, she feels doubtful in her abilities to protect the world and its Leafe, the source of energy for all life. Will Himeno be able to find happiness among her new family and also save the Earth from the enemy, the Princess of Disaster?