Book 2 of The Expanse series by James S. A. Corey is a fantastic follow-up that pulls off the unusual feat of being a better book than the first book in a series.
This one follows James Holden and his small crew as they find themselves once again in the middle of events swirling around the solar system. On the “other thread” you get to meet U.N. Undersecretary Christen Avasarala and see her fight a political battle against nearly insurmountable odds. The third major character is Bobby Draper, a Martian marine who encounters and survives an early protomolecule monster encounter.
All of this maneuvering occurs under the ominous transformation occurring on Venus after the events of the first book sent the protomolecule there, instead of Earth.
Along the way, you get to know these extremely interesting characters, see them change, and handle some pretty sticky dilemmas in creative ways.
Overall, while the Expanse books fall into the category of “Space Opera,” I’d caution you against thinking of them that way. Space Opera has become synonymous with the concept of cliche space stories. They reuse and recycle old themes, characters, and situations and you end up with very similar stories. Sometimes it’s just a re-worked western set in space. They tend to be fun, fast reads, but the common theme is cliche. There is essentially nothing cliche about these books. They are original and gritty. The characters are far outside the norm, and you get to know them and their motivations very well.
Add to that the fairly realistic way in which real physics are dealt with, and you give the story a bit of a hard science-fiction edge.