Volume 5 is divided into 2 main storylines.
1) As the Rebellion scores a great victory over the Empire on Bar'leth, a call goes out across the galaxy from Qi'ra, waking Crimson Dawn sleeper agents. Two such agents, Jon and Bevelyn, are stationed in an Imperial Black Facility that develops weapons, and they decide that they need to take their two kids and run, hoping to hook up with the Rebellion. They are barely able to escape, and need a final rescue from Luke to get safely to the Rebels. Their most valuable info? The existence of a second Death Star.
2) Needing a vacation, Leia and crew (Luke, Chewie, Lando, Lobot, and Holdo) head to Spira for R&R. That's not all Holdo has in mind for them as there is an antiques auction being held. Her target, an old High Republic era Nihil Strikeship. She wants the Path Engine from it, which she hopes will give her the coordinates to the Kezarat Convoy, a lost "treasure" ship of sorts. Losing the auction, but liberating the Path Engine, they use it to jump to hyperspace.... but end up in No-Space, a Nihil stronghold only accessible by Path Engine. They find the Kezarat Colony ship, but are told they'll never leave No-Space because no one ever has.
Overall, another good Volume from Star Wars.... should be getting closer to RoTJ. Still want to see the building of the green lightsaber...
Recommend. Most Star Wars stuff is really good.