Book Review // Horus Heresy Gunsight by James Swallow

Let’s ride the Horus Heresy train again! I’m powering through the War Without End series, and today’s title drops us straight into the beating heart of heresy: Gunsight. It’s always a treat when we get a Heresy story without Space Marines as the focus. A little fresh oxygen. A different view of the galaxy. A reminder that this war crushes more than just Astartes.

So, here are the details.

Details

Title: Gunsight
Author: James Swallow
Fluff: An assassin lurks aboard the Vengeful Spirit. His target? Warmaster Horus himself.
A story set within the flagship of Horus Lupercal, where a killer prowls the corridors and another attempt on the Warmaster’s life begins to unfold. Many have tried. All have failed. Will this be any different?

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The Review

Right away, I was thrilled to realise this is a follow-up to Nemesis, still one of the standout tales in the entire series. And, thankfully, Gunsight does not disappoint. If anything, it leans even harder into that tense, cloak-and-dagger energy, slipping in a few twists I genuinely didn’t see coming.

Much of the story’s enjoyment relies on the mystery surrounding the assassin’s identity, so I won’t spoil that payoff. But I will say this: the reveal is worth the wait. Another unexpected highlight is a secondary character who might just be the last loyal crewman on the Vengeful Spirit, and through absolutely no choice of his own. Watching him navigate a crew already halfway claimed by Chaos is unsettling and oddly tragic. Is he loyal? Damned? Or simply surviving? Swallow leaves the line deliberately blurred.

But let’s talk about the real star: the Vengeful Spirit itself.

This story gives us a rare, intimate look at the sheer scale of Horus’s flagship. Endless decks. Hollow chambers. Forgotten corridors. Vast stretches of shipboard emptiness where a person, or assassin, could disappear for months. Getting to explore the inner layers of one of the most infamous vessels in the galaxy is pure Heresy-reader candy. More than once, I caught myself thinking: “Oh yeah… this thing is basically a continent with engines.” The sense of the place is incredible, and it elevates the whole tale.

Overall, Gunsight is a fantastic story, and yet another reminder that I should’ve read it earlier in the timeline. As a follow-up to Nemesis, it absolutely earns its place among the great assassin stories of the era.

As always, thanks for reading and stopping by. More Heresy chatter to come!