This review will contain some spoilers for the previous two books, Transformers: Exodus and Transformers: Exiles, as well as the related Transformers Prime television show and the video games War for Cybertron and Fall of Cybertron.
Transformers: Retribution brings a new author to this trilogy of books with David J. Williams and Mark Williams picking up where Alex Irvine left off. And it shows, it certainly shows. Retribution is a significant improvement over the last two installments, with clearer details and more attention paid to continuity. Despite that, having to continue the story from the mess that was Exodus and Exiles does prevent this story from doing as much as it could have stand-alone.
Picking up where Exiles left off, the Decepticons are in pursuit of the Autobots with the space pirates the Star Seekers after them both. The Star Seekers are one big issue with this book, as their story is left unresolved and they never popped up further down the continuity line in Prime. One other major issue with characters is the sudden appearance of the Aerialbots, a group of flying Autobots, on the Ark. The last book repeatedly showed Silverbolt as the only flying Autobot onboard, which constantly left the Autobots at a disadvantage against the flying Decepticon Seekers throughout the story. No explanation is given as to what the Aerialbots were busy with during Exiles.
All things considered, the transition from Irvine to the Williams went pretty smoothly. We were given lots of details that were nowhere to be found in the last two books, such as more descriptive action sequences and actual physical descriptions of the characters that Irvine never bothered with. Ultimately, having to clean up after Irvine was just too much for one book to do. If the Williams had more page space they probably could have done it, but even by the end of Retribution there is still a lot of time where who knows what happened between here and the start of Transformers Prime.
For die-hard Transformers fans, this book is recommended. While it is not the best, it is still part of the Aligned continuity family. Important bits of the lore that could still be relevant, as the Aligned universe is still being added to, are introduced here. Not to mention all the nods to the original Generation 1 series. But for general sci-fi fans or the casually interested, this trilogy can probably be skipped. Just play War for Cybertron and Fall of Cybertron instead.