This is the Avenchurin Kingdom.
One day a great accident befell the kingdom.
The beautiful prince Legrand fell into a deep sleep because of the curse of a forbidden magic book.

The day of the prince's succession test is in one hundred days, somehow the curse has to be dispelled before then.

It is written in a legend that in order to dispel the curse you need a special 'magic stone' with great power.
That stone is a troublesome thing that chooses the ones who can use it and also needs to be charged up by people it chooses.

The one who is chosen by the stone is a one of the 'Ripple' Court Magician apprentices Crim.
She also has a rival apprentice Richil.
The ones chosen to power up the stone are the princes of the six countries of Water, Fire, Wind, Earth, Flowers, and Snow.

From now on Crim and the six princes have to work together to power up the magic stone and dispel Legrand's curse before the succession test.

[Translated from the official site]