Graham McNeill’s Horus Heresy novel Mechanicum is book nine in the series, and McNeill’s third contribution, but it’s a book of firsts as well – the first proper look at Mars and the Mechanicum (ever, really, but certainly in the Heresy series), the first depiction of Imperial Knights in Black Library fiction, and the first female-led Heresy novel. Young scribe Dalia Cythera is whisked off to Mars by Adept Koriel Zeth, who puts her innate understanding of technology to use working on a ground-breaking project. Meanwhile tensions are mounting between rival factions on Mars, even bringing the Titan Legions into conflict.
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