When an archaeologist excavating a top secret historical site realises the magnitude of his discovery he requests help from treasure hunters Sam and Remi Fargo. And in rushing to join him, the husband and wife team are thrown into their most daring quest to date.

It is 1907. Train wrecks, fires and explosions sabotage the Southern Pacific Railroad's Cascades express line. Desperate, the railroad hires the fabled Van Dorn Detective Agency. Van Dorn sends in its top investigator, Isaac Bell, who quickly discovers that a mysterious saboteur is responsible for the railroad attacks.

Treasure hunters Sam and Remi Fargo are exploring the Great Pocomoke Swamp in Delaware when they are shocked to discover a WWII German U-boat. Inside, they find a bottle taken from Napoleon's 'lost cellar'. But someone else wants the bottle, and he'll do whatever it takes to get it.

December 1941. Four brothers investigate the secrets of a treasure pit on a small island in the Pacific. But a sudden death and the coming war allow its secrets to lie forgotten. In the present, Juan Cabrillo and the Oregon team make a mysterious discovery which sends them to that same island.

It is 1908, and internatonal tensions are mounting as the world plunges towards war. When a brilliant American battleship gun designer dies in an apparent suicide, the man's grief-stricken daughter turns to the legendary Van Dorn Detective Agency to clear her father's name.

Scuba diving off the Tanzanian coast, husband-and-wife treasure-hunting team, Sam and Remi Fargo discover a huge ship's bell, covered in cryptic carvings. But as they struggle to first recover the bell and then decode its clues, they find they are not alone in wanting to discover its secrets.

Detective Isaac Bell embarks on his most dangerous case yet. Aviation is still in its infancy, and Preston Whiteway is offering $50,000 to the first pilot to cross America in less than 50 days. One of the candidates is Josephine Frost. However, her husband is on the run after killing her lover and trying to kill her.

The husband and wife team of Sam and Remi Fargo are used to hunting for treasure, but they aren't used to hunting for people - until an investigator friend of theirs goes missing, and they promise to search for him. What they find, however, will be beyond anything they could have imagined.

In the Black Sea, Kurt Austin and the NUMA team discover an abandoned submarine base commandeered by a mining tycoon who claims Romanov ancestry. Backed by his incredible wealth, the tycoon has proclaimed himself Czar of Russia. He is determined to overthrow the already shaky Russian government.

Giant freak waves send an unsinkable cargo ship to the bottom of the Atlantic and a herd of killer whales attack a party of kayakers in the Pacific - random events, or evidence of polar shift? For Kurt Austin of NUMA these two seemingly unconnected incidents are harbingers of a global phenomenon that will mark the end of civilization.