Zhè běn xiǎoshuō jiǎngshù le yīgè yìjiàotú de gùshi.
This novel tells the story of a heretic.
Tips
usage
异教徒 carries a negative connotation from the perspective of the dominant religion, similar to English 'heretic.' The related term 教徒 (jiàotú) simply means 'believer/follower' without the negative sense.