Spock had gone to Romulus to bring the emotional, warlike Romulans the way of Surak. Although he started out as an outcast, through the years, he has risen to a place of some prominence among the Romulans, despite being Vulcan.
The Romulan Empire is beset with a problem. A Star in the Hobus system has gone out of control, threatening to go nova. Just one of its solar flares destroyed an entire planet. However, this is different. With each eruption, the energy of the star is increasing synergystically with everything it destroys. Spock believes that if and when the Star goes nova, it will spread out to nearby Star Systems, destroying and absorbing their energy as well. If that happens, the entire Romulan Empire could be imperiled or destroyed, as the repercussions and the energy expand outward in ever-increasing waves.
The Romulans aren't ready to accept that their Empire could be at risk, but he invites their scientists to check his figures. He does have an idea on how to stop it before the star goes Nova. There is a mineral called Decalithium, a rare isotope that can create something called "Red Matter" The Super-dense Red Matter could make a small black hole- large enough for it to swallow the Hobus star before it goes Nova.
The Romulans don't trust Spock, and their scientists don't forsee the same Cataclysmic reactions that Spock does. So they turn down his proposal. However, a young mining guild representative named Nemo has witnessed the Star flare of the Hobus system himself, and he trusts Spock. He tells the Ambassador that he will put his mining ship at Spock's disposal to mine the Decalithium and stop the Hobus star.
Leaving his pregnant wife, he and his crew travel to a small world on the furthest-flung edge of the Empire to mine a deposit of Decalithium. But once there they come under attack by the Remans, but are saved by the timely appearance of the Enterprise, under Captain Data. Starfleet has learned of the threat of the Hobus Star, and is working with the Vulcans to stop it.
Meanwhile, the Romulans have come around to believing Spock was right. But they also believe that Spock will abandon Romulus to save Vulcan. They believe that the only way to survive is to abandon Romulus and attack Vulcan. Meanwhile, Spock, Data and Nemo land on Vulcan, where they meet with the Vulcan Science Council. The Vulcans don't want to work with the Romulans, and believe they cannot let the fruits of Vulcan science fall into the hands of the Romulans. Nemo feels frustrated, being stuck on Vulcan, unable to do anything while the Council debates. Even the presence of Ambassador Picard can't change his mind.
so when the Hobus star goes Supernova, he heads back to Romulus to save his family. He tells Spock that if Romulus dies, he will blame the Vulcans. But he's too late, and the entire world is destroyed. Almost immediately, he swears vengeance, along with his crew. When the crew picks up a group of Senators from Romulus, Nemo kills the Praetor whose vote in Council doomed Romulus, but he and his crew find out the location of a secret Romulan weapons and science research station. They will need weapons for their attack on Vulcan...
While back on Vulcan, the Decalithium is turned into Red Matter. Now they just need to find a way to fire it into the Hobus star. Their solution is a ship called "The Jellyfish", made to withstand pressures no other starship can withstand. And with it comes Geordi LaForge, its designer. But even as Spock prepares to leave for Hobus, Nemo and his crew are taking their revenge on the Empires around them, testing out the new weapons their ship was given. But can Spock save the galaxy from the Hobus nova... and Nemo and his grief-stricken, vengeful crew? That remains to be seen.
This story is a prequel to the new Star Trek movie by J.J. Abrams. It sets up the backstory for the main villain of the movie. I am assuming that the black hole produced at the end of this tale is how both Nemo and older Spock get back from the future (okay, I didn't see the move, so I'm not sure what happened in it-lack of money and time, not lack of interest). It's a very effective tale. You can see why Nemo was out for revenge, and yet feel sympathy for him because of what he lost.
At the same time, the Vulcans and the Vulcan science council end up being as blindsighted as the Romulans, making you wonder how the Vulcans can claim to be better or more civilized. It's like they merely pay lip service to the Principles of Surak when they refuse to work with the Romulans. Surely it would be logical to save their lives and come off better so that more Romulans feel grateful for their cousins, but instead, they decide to remain mired in fear, anger and revenge- and the Federation does nothing. This series has definitely moved far away from "The Future Will Be Better" that Gene Roddenberry espoused.
I enjoyed this book, but it was also a little annoying to see that the Vulcans, basically, can be no better than the humans when it comes to emotion. Neither the Vulcans nor the Federation come off well, and that did make me a bit sad. But I would definitely recommed this series to anyone interested in Star Trek- it just may shatter the illusions of someone who actually watched the original series.