Starwars.com has posted a summary of the plot for this much-anticipated conclusion to the New Jedi Order.  Here's a taste:

"The stage is set for endgame:  Luke, Mara and Jacen desperately try to recruit an unwilling ally for the Jedi's final campaign against the Yuzhann Vong.  Han and Leia learn that hundreds of high-ranking Alliance prisoners face slaughter in a sacrifice to the enemy's bloodthirsty gods.  And a lone space station is all that stands between the Alliance headquarters on Mon Calamari and endless waves of enemy forces waging their most decisive assault."

Visit the Official Site for the full text, including information on a bonus CD-ROM to be included with the book (cover art shown below still in development).