It's a skilful author who grips the reader from the first word. From its killer opening line to the dazzling denouement Carter Roy's debut novel ''The Blood Guard'', a popular nominee for the 2015 Northern Ireland Book Award, delivers. This fantasy extravaganza, aimed at readers aged 10 and up (that includes enthusiastic adults), starts with an unusual premise. It is based on the legend of ''tzadikim nistarim'' (the 36 hidden righteous ones) which can be found in the sacred text of Judaism, ''The Talmud''. This tome states that the existence of these 'pure' people are the reason the Earth does not perish in fire ignited by the hand of God.