Mars Xi evaded capture by the military research team who shaped her, and honed her psychic abilities into near god-like powers. But can she rescue her friend from a max security military prison before he loses his mind and his identity?

For a chapter, it seems like Void Black Shadow starts with time to catch our breaths and set up the next part of Mars Xi’s story. Then the ship starts crashing into atmosphere, and Mars is doing her best to save skins and take heads.

But this is a small book with a big story to tell: a chapter is all Corey J White can afford to spend on set-up. Still, it gave me time to marvel that Mars is developing a softer side based on her interactions with Pale, the boy she rescued from MEPHISTO. A brief appearance by Miguel provoked more complicated feelings: her old ally has grown deeply afraid of her. It’s remarkable, really, how thoroughly White manages to (re-)establish characters and set the scene before the explosions begin.

Trix’s lover Mookie was captured when Mars went toe to toe with MEPHISTO. Miguel promises that a MEPHISTO data facility will hold all the answers Mars needs – about Mookie’s whereabouts, and about the program that created her and Pale – but the crew find themselves facing a new threat: the cyborg soldiers of the Legion hive mind. As they uncover horror after horror on the base, Mars allows herself to be captured by the Legion and sent to the same prison holding Mookie.

It’s a heck of a gamble.

Like Killing Gravity, Void Black Shadow is a pitch black space opera. We’re given an unflinching look at the medical process that created the Legion, and how it ruthlessly overrides the free will of those ‘recruited’ into it. Our villains are military doctors who refuse to consider that even criminals and dissidents have rights, and prison guards who enjoy the sharper end of their job a little too much.

…and the prison turns out to be perfectly designed to protect them from Mars’s inhuman abilities. I’m not a big fan of prison narratives (and Shadow adopts many familiar tropes), but having established Mars as an unstoppable force, White does well to rein her back in, injecting tension back into the proceedings.

The stakes here are high because they’re personal. If Mars fails, Mookie will be co-opted into the Legion. She herself will be killed or broken and returned to the emperor’s service (there’s an emperor! I missed that in Gravity), her identity subsumed as surely as Mookie’s. Mars not only has to figure out how to save them both, she has to deal with violent aggressors, torture and time to reflect.

Where Gravity simply stacked up the bodies with a merciless, remorseless Mars at the centre, Shadow – thankfully – begins to turn the lens on how monstrous her actions are. Mars almost always reaches for violence as a solution and never embraces half-measures. Does fighting a deeply dystopian force really excuse the mass murder she routinely engages in?

As she acquires a rising horror of what she does, we get ripples of her guilt and shame. Not that this holds her back: when she has an opportunity for revenge, she still goes full throttle. But it’s an oddly reassuring piece of character development in a series that could otherwise lean towards space gorenography, and it gives me hope of a more intimate, inwardly-focused finale.

Void Black Shadow is a hard if fast read. I’m not going to say anything about Mookie because spoilers, but oh my word it’s harrowing – if satisfying (although I felt that Trix’s guilt was perhaps an overwrought step too far). I appreciated the greater emotional weight of this story and enjoyed the glimpses of broader context. It also left me curious about the Empire – is it as dystopian as its secret military arms? Does the Emperor know what is done in his name? I don’t expect to have these questions answered in Static Ruin and that’s okay: this is Mars’s tale, and I can only hope she finds peace at the end of it. One way or another.