Kaine's Reparation

Saving humanity and ending it look like the same decision.

Ten years ago Hayden Kaine made the jump gates to go dark to stop an invasion. It worked.
It also left a thousand worlds isolated, leaderless, and defenseless for when the enemy came back.
Now they are returning.
Kaine and the crew of the Scimitar have spent two years hunting a piece of alien technology the old empire called the cynosure — the only thing that could reconnect human space. Everyone with power wants it for the same reason: whoever controls it decides what civilization looks like next.

Then they learn what the Malliac have already deployed while humanity has been busy fighting itself.
Kaine finally has the tool to undo the damage he caused. Using it will prove it can be used as a weapon. Not using it guarantees extinction. And the ancient system he is about to touch was never built for human hands.
There are no good options. He still has to choose.

This is military science fiction about competent officers under impossible pressure, where knowledge doesn't give any advantage — it traps you. 
If you liked The Expanse because survival depended on competent people inside broken systems making choices that stick, you will feel at home aboard the Scimitar.
If you liked Dune because power and knowledge become a burden, not a gift, this is that kind of story.
Kaine's Reparation is Book 3 of the Shattered Empire series.

You don't know who you are until it costs you.