Halo: Ghosts of Onyx is the title of the next Halo book by Eric Nylund. Published by Tor, it is due to be released on October 31st, 2006.
In addition, the announcement of the title also included a confirmation that Ghosts of Onyx is not the last planned Halo book. At least two more novels are planned to follow it, this is part of the contract with Tor.
Plot
The official summary is:
The Spartan-II program has gone public. Tales of super-soldiers fending off thousands of Covenant attacks has become the stuff of legend.
But just how many Spartans are left?
While the Master Chief defends a beseiged Earth, and the myriad factions of the Covenant continue their crusade to elliminate humanity, an ultrasecret cell of the Office of Navel Intelligence known as "Section Three" devises a plan to buy the UNSC vital time. They're going to need hundreds of willing soldiers, though... and one more Spartan to get the job done.
The planet Onyx is virtually abandoned and the perfect place to set this plan in motion. But when the Master Chief destroys Halo, something is triggered deep within Onyx: Ancient Forerunner technology stirs, and fleets of UNSC and Covenant race to claim it to change the course of the Human-Covenant War.
But this reawakened and ancient force may have plans of its own...
This possibly involves Dr. Halsey and Kelly, as well as CPO Mendez, and the possible next generation of Spartans.
Through the leak of the working title, "Halo: Ghosts of Coral", it was speculated to be about the planet Coral, which is the site of excavations that have uncovered Forerunner artifacts (see Conversations from the Universe), though this speculation is most likely not valid because of the announcement of the real name.