From the back of the book:
A new power is born
The battle of the boys and girls begins
This book "Soul Arts" is a sourcebook for "Night Wizard! The 2nd Edition" containing a replay and additional data. It contains the replay "The Lights in The Sky are all Stars" depicting the battle between a boy who has awakened to to a new wizard's power as a "medium tuner" and emulators on the stage of the average rural town Aratoyama-shi as well as additional data starting with two new wizard classes.
The newly awakening wizards
Ever since the magical warfare, the world kekkai's weakening has been significant, and even now the world is on the brink of danger. But, at the same time, the number of newly awakening wizards is increasing. The two classes added thanks to this book are also symbolizing this new wizards' power. The "medium tuner" who fights projecting the powers of wizards remembered by the world into their other self, the "medium", and the "broom rider" who has specialized in the usage of "brooms", the symbol of present day wizards. Protect the world with new powers, magic users of the night!