A thief boards a river barge carrying his possessions with orders to destroy Jefferson's research on American Indian languages.

However, some materials survive, including a vellum with Phoenician writing Jefferson obtained from the Unkechaug tribe on Long Island.

Jefferson believes the vellum reveals that the original tablets of the Ten Commandments were concealed in King Solomon's Mines in North America.

Worried that the discovery will lead to unchecked westward expansion, he sends Louisiana Territory governor Meriwether Lewis a coded message concealed as an article about artichokes.

After she leaves, professional assassin Adriano meets with Ali to discuss the purchase for businessman Viktor Baltazar of the Navigator, a bronze statue that shows an ancient Phoenician mariner using a compass.

She purchases them with Baltazar's funds and places them on the container ship Ocean Adventure to the U.S. where she plans a museum tour to raise awareness on losses to Iraqi heritage.

After tying up Mechadi and the crew, they prepare to remove the Navigator by helicopter and set the ship's autopilot on a collision course with an oil rig to eliminate evidence of their attack and kill witnesses.

National Underwater and Marine Agency employees Kurt Austin and Joe Zavala, who were on the ice patrol ship to learn about iceberg wrangling, intervene.

With Zavala's aid, Austin boards the container ship from a boat, frees Mechadi and the crew, and prevents the hijackers from taking the Navigator although they escape.

At the American Philosophical Society in Philadelphia, assistant librarian Angela Worth helps writer Norman Stocker research a book on artichokes.

Also present are Baltazar and Anthony Saxon, an amateur archaeologist who has written books arguing Phoenicians actively traveled to North America.

Austin and Mechadi travel to Istanbul and meet in the Basilica Cistern with antiquity smuggler Cemil who directs them to a shop in the Grand Bazaar selling the figurines.

They hire a boat and are joined by Zavala, who was in Istanbul helping to excavate ancient harbor facilities and brings a wet submersible resembling a Corvette.

They locate the ship and find the remains of another wreck diver who was wearing World War II-vintage diving gear.

Zavala and fellow NUMA employees Paul and Gamay Trout dive in the now-flooded cave and find the relic was previously removed by Jefferson, who used the site to conceal the complete map of Solomon's mines instead.

Austin escapes and Baltazar flees to his ancestral home, a castle in Cyprus, planning to sacrifice Mechadi to Baal, a Phoenician deity still worshiped by his family.