Freeheads is the final book in the sci-fi series: "Dark Trench" by Kerry Knietz.
From the "back of the book":
"Having escaped the storms of Betelgeuse and the schemes of Jannah's inhabitants, Sandfly and HardCandy make their way back to Earth. They have a message to deliver. A society to free. And A~A3 is with them. Their mission is simple, and just. What could possibly go wrong?
Unexpectedly, DarkTrench drops into normal space. He is malfunctioning, wounded, and the only people who can fix him are still hundreds of light years away. Sand and Hard scramble for a solution while catastrophe hurtles blindly toward them.
They reach Earth to find a different world, an unexpected domain. One they can no longer connect with.
They are stranded, hopelessly separated beneath a wasteland of death and a planet of rules. Debuggers amidst a cloistered community.
Ultimately, Sandfly is alone, and Earth's freedom relies on him and his newfound faith. But does his mission even matter anymore?
He's a misfit, and a throwback. A symbol for all that's evil.
Perhaps he's the last freehead?"
Lots of characters from book one return here. ;)
Freeheads picks up right where The Superlative Stream left off. There are a lot of surprises in this book, but looking back to the first two books, all of them were foreshadowed, and the plot twists all dove-tail nicely into the rest of the series.
The writing is at it's best in this book. Characterization is great, and the balance of inner thoughts and external action is just right. I don't want to to give away how it ends, but the ending is great. Freeheads is my favorite in the series.