Weapon of Atlantis

There are 6 books in the Atlantis series: Hidden Courage; Tomb of Atlantis; Curse of Atlantis; Tomb of Zeus; Atlantis: The Crystal Scepter; and Atlantis: The Sacred Orb (release on December 14th, 2014). Please see recommended order of reading below.

Hidden Courage: is the back story of the main character in the Atlantis series (Interesting, but not essential)
Tomb of Atlantis: is book 1
Curse of Atlantis: is book 2
Tomb of Zeus: is book 3
Weapons of Atlantis: is book 4
Atlantis: The Sacred Orb: is book 5

Weapons of Atlantis:
Jack Roberts and Javier Arista have made a startling revelation: an alien spacecraft may exist under the ice in northern Greenland. As the two rush to the icy location in search of the seven thousand year old object, "others" are in hot pursuit.

After a harrowing near-death catastrophe, the two find what they were looking for, but the magnitude of their discovery is far greater than they ever imagined. Buried deep within the crafts mission log, a secret weapon exists and government agents will stop at nothing to have it.

Now, armed with blackmail, the agents force the two to do the impossible: locate the site of the alien secret weapon. Their journey takes them far beneath the ocean's surface where tragedy and death seem to be a foregone conclusion. Only a miracle will save them.