The story of a remarkable boy called Yann Margoza; Tetu the dwarf, his friend and mentor; Sido, unloved daughter of a foolish Marquis; and Count Kalliovski, Grand Master of a secret society, who has half the aristocracy in thrall to him, and wants Yann dead. Yann is spirited away to London but three years later, when Paris is gripped by the bloody horrors of the Revolution, he returns, charged with two missions: to find out Kalliovski's darkest deeds and to save Sido from the guillotine...