Nina, thinking it was a lolly, swallows an object called "Crystal Pearl". But the candy turns out to be a test for the magicians. To retrieve the crystal, a special medicine has to be made so now Zero and Ichii, the magicians, have to protect her from others while waiting for the medicine to be completed.

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.

Three years has passed since the events of the first series. Hiromi continued training with her coach and became Japan's junior champion. Their common profits have also contributed to the coach being chosen as the first trainer of the Japanese Selection of Tennis and is arranged to head a trip with the youngest members of the team to USA. The relation between Hiromi and its trainer is narrower at personal level but it exceeds the teacher-student bond with great difficulty. (Source: AniDB)

A special episode focusing on the story of Merm4id and Rondo, including a new, joint performance by the two groups.