Magico has been serialized in the Japanese magazine Weekly Shōnen Jump, published by Shueisha since February 2011. As of April 2012, Shueisha has compiled its chapters into five tankōbon bound volumes.
Emma, a country girl, first came to the city to start a new life after having been isolated since early childhood. But for some reason, when she entered the city all the young men and even the king tried to forcibly marry her. And when it seemed that there was no hope left but to marry the king, a dragon comes crashing into the room. To everyone's surprise, a young man named Shion comes out of the dragon's mouth. He "saves" her and they leave. Later on, he explains to Emma about her history and how she is the legendary Echidna, a power born every 500 years so devastating that in the wrong hands, could mean the destruction of the world. Shion goes on to tell her that she will be a target to all mages that seek her power. He goes on to speak of a ritual that could change her destiny. This ritual is called Magico. And to complete this ritual they would have to perform and complete many difficult tasks to seal the magic of Echidna away. The first of which is to marry Shion!? What other tasks remain for these two!?