However, his retirement is thrown out the window as the aggressors that were defeated three years ago viciously attack and destroy the Claymore, a Glenlyon destroyer escorting a freighter, when they jumped into Jatayu on their way further down the line. It seems that Scatha, Apulu, and Turan are working together to subject and conquer nearby systems and are ramping up to a full invasion of Kosatka. The Glenlyon government calls on Rob to return and captain their only ship... but that's something that the current Captain might have objections to.
With the Sabre (Glenlyon's only remaining destroyer) and its staunch, by-the-checklist Ex-Earth Fleet crew under his command, Rob takes Mele and her fledgling Marines with him to respond to the attack. Rob will have to gain his crew's confidence and show them that there are times that quick thinking and out-of-the-box strategy can be more useful than tried-and-true checklists, if they're to survive with one ship against unknown odds.
Meanwhile, the colony at Kosatka has been under attack for a while by a group of invaders, but now Scatha has entered the Kosatka system claiming the invaders are colonists from Kosatka and that it's actually a civil war. Scatha claims to be stepping in on a humanitarian effort to offer aid, taking Kosatka into its protection and considering other ships approaching to be an act of war. This appears to be an attempt to prevent other systems from coming to Kosatka's aid and, being basically blockaded from getting any outside support, Kosatka's in dire straights.
Luckily for Kosatka, once Rob Geary frees the freighter that had been captured in Jatayu, he turns his attention to Kosatka, having discovered that the would-be empire is planning a major attack there. But, with command of the one warship left in Glenlyon's "fleet," can he risk coming to Kosatka's aid, or should he return to Glenlyon? It's not an easy or straightforward decision to make; he can't leave Glenlyon unprotected, but if he assists Kostaka now, he may make all the difference... and, hopefully, finally gain an ally to fight against threats in the future. Worse yet, there's no way to communicate back with Glenlyon without returning and the delay would cost him any possible advantage. The book clearly says to return home... but Rob's never been one to go by the book...
I am enjoying The Genesis Fleet immensely. Ascendant delivers more outside-the-box, by-the-seat-of-your-pants and by-the-skin-of-your-teeth sort of action, adventure, and espionage, not only by Rob Geary, but by Mele Darcy and her marines, and even Lochan Nakamura, a politician who starts out representing Kosatka to find allies and finds himself in some sticky situations with a new... and unexpected... friend.
If you like innovative thinking in your spaceship battles and you're looking for some espionage and adventure in high space, I highly recommend Ascendant. However, if you haven't read the first book in the series (Vanguard), you owe it to yourself to start there.