This is the second part of the Vanguard-saga. It pushs the plot farther down the road towards open conflict - with the Shedai, and the neighbouring races. And it thickens the tension for the characters themselves.
First things first.
Another of the Federation research outposts, this time on Erilon, is destroyed by a seemingly all-powerful creature, killing the captain of the Endeavour and almost obliterating the ship itself in orbit around the planet via massive planetbound weapons. Those creatures are mere avatars for one Shedai, the Wanderer - and one of them can be obtained in a follow-up mission to Erilon and reveals itself being constructed with the metagenome that's led the Federation into the Taurus Reach in the first place. And an autopsy of one of the victims shows alien DNA that has close similarities with Tholian DNA.
But not only the Federation but also the Klingons suffer losses. The Wanderer destroys one of their colony worlds, Palgrenax.
The Tholians won't just idly sit by and watch others invade the Taurus Reach, a region of space long feared by them because of the history with the Shedai, and start attacking Klingon ships as well (after destroying the Bombay in Harbinger). This leads to both the Klingon and Tholian ambassadors recalled to their respective homeworlds from Vanguard, just when Jetanien is making some headway into the secrecy surrounding the Shedai and the Tholian involvement. But surprisingly, his efforts seem to have payed off in at least so far as the Klingon ambassador Lugok contacts him, and a way to backroom diplomacy appears to have opened up.
Cloaked the Romulans observe what happens in the Taurus Reach - and come to the decision to reinforce their efforts against the apparently expansionist endeavours of the Klingons and the Federation. They plan to attack Federation outposts on the border of the Neutral Zone (which will lead to the events of Balance of Terror).
Meanwhile, T'Prynn uses Quinn and Pennington, who decided to throw his lot in with the mercenary to get out to the colonies for new story material, to obtain sensor data from a Klingon probe which points to the Jinoteur system, a system suspected as source of the unusal frequencies which so disturbed Vanguard's operations during its construction. It reveals a system of planets and moons which seems to be contructed artificially - and, therefore, is the next target for research.
On the character front:
Desai and Fisher, Reyes' two closest confidants on the station, are read in in parts on the Shedai situation. Reyes himself continues to have doubts about the cover-up Starfleet is demanding and reaches out to Pennington, telling him that he screens the reporter's stories and that a compromise can be reached as long as Pennington's stories don't put Vanguard and its operations in danger.
T'Prynn is getting ever more affected by Sten's katra and starts to display unusual behaviour, so far only noticeable to those who are used to watching their surroundings. But she manages to turn her lover Anna Sandesjo into a double agent.
Last but not least, the Endeavour and her crew are introduced, as well as the Lovell and her crew of engineers.
"Summon the Thunder" might not be as fast paced as Harbinger but it further sets out the plotthreads which will start coming together with the next installments, such as Reyes and Pennington's collaboration, or Jetanien's efforts at bringing the Klingons and Romulans to the negotiating table, not to mention the onsets of T'Prynn's mental breakdown. It is really interesting to read this book, already knowing what will come of all of this, seeing the bigger picture when there are still just a few pieces laid out.
The crew of the Endeavour are a calmer bunch than the Sagittarius, with fewer quirks, and thankfully, fewer witty one-liners. But as far as the Sagittarius managed to annoy me, the Endeavour still remains a bit bland. As it seems that the 3 authors decided that Mack would primarily write about the Sagittarius and Ward/Dilmore about the Endeavour, I'm curious to see how this will play out. Right now - and of course, also judging from the books that come after this one -, I'm favouring the Endeavour crew. Actually, though, I quite enjoyed the little glimpses into the crew of the Lovell, especially al-Khaleed who worked with Ming Xiong on Erilon and displayed quite a calm and competent state of mind in the face of almost certain death. Since the Lovell is featured in quite a few of the S.C.E.-novellas I might pick up on of those at some point to learn more.
A good book lives and dies with its main characters. And here all of them are allowed to grow quite seemlessly from the events depicted in Harbinger. Reyes is driven by his need to protect those under his command - and haunted by the fact that he couldn't in the case of the Bombay, partly because he's sworn to secrecy and therefore putting lives at risk who don't even know what they're getting into as is the case with the colonists trying to make a living in the Taurus Reach. He's also a deeply moral person, not comfortable with the decisions that led to Pennington's fall from grace - but also not really able to do something about. But he's approaching a line he won't be willing to cross, perhaps even more so now that Desai and Fisher, the station's CMO and Reyes' friend for decades, are read in and able to be a sounding board to Reyes' doubts.
The twist that T'Prynn managed to turn Anna Sandesjo into a double agent comes quite as a surprise. Now what? Is she willing to sacrifice Sandesjo? Did she enter the relationship because of genuine feelings or out of the need to turn her? And just how much did Sten and the fight against him influence her decisions, and emotions - and her morals? By this book, though, T'Prynn's without a doubt willing to sacrifice everything for the cause - seemingly without conscience, although that might soon change as evidenced by her unknowingly seeking out Pennington's quarters. She's one of the most interesting and multi-faceted characters in this series, but likeable she's not.
I still don't quite see the point of Quinn and the Orions (despite knowing the part of the story they play in the bigger picture). I feel that too much of the story is spent on them, on a minor playground if you will. Quinn (and Pennington)'s adventures take a bit too much space in this book, especially all those intrigues that are aimed to dispose of him. And just what was the point in retrieving that accountant? Even if it's important to obtain the sensor probe's information, the part about the Zakdorn could have been cut or at least reduced to the mere basics when all he does is die anyway.
Jetanien's efforts seem to have failed - but for the communication from Lugok. But what now? The ambassadors left the station, what's left for Jetanien to do?
Overall, Summon the Thunder is a really good book, advancing the story on multiple levels. Definitely a worthy follow-up to the excellent Harbinger - and a beautiful setup for the climax of the Vanguard-series. 8/10