Amy Wild's first day at her new school is disrupted by the appearance of an uninvited guest, when Mozart the music-loving mouse joins in the children's singing lesson. The head master is not impressed and threatens to get rid of Amy's friend, Einstein the school cat, if Einstein does not get rid of the mouse.Amy Wild's first day at her new school is disrupted by the appearance of an uninvited guest, when Mozart the music-loving mouse joins in the children's singing lesson. The head master is not impressed and threatens to get rid of Amy's friend, Einstein the school cat, if Einstein does not get rid of the mouse.