Deep below the Atlantic Ocean, guarded by hundreds of dolphins, lie the astonishing remains of an Atlantis-like lost city called Marinth. Its disappearance has confounded scientists for years--until now. Marine architect Hannah Bryson has unearthed a legendary artifact that might hold the key to unlocking the city's long-buried secrets. But Hannah's discovery could have dire consequences for the modern-day world--and there are some people who will do anything to keep the truth about Marinth hidden...

When the artifact is hijacked, Hannah stands alone between a power-hungry enemy and...