"The dazzling new novel in the #1 New York Times-bestselling series from Clive Cussler, the grand master of adventure. When Kurt Austin is injured attempting to rescue the passengers and crew from a sinking yacht, he wakes with fragmented and conflicted memories. Did he see an old friend and her children drown, or was the yacht abandoned when he came aboard? For reasons he cannot explain, Kurt doesn't trust either version of his recollection. Determined...

After an undersea lab conducting research on a rare jellyfish known as the blue medusa mysteriously disappears and a bathysphere harboring Joe Zavala is attacked by an underwater vehicle and left helpless on the sea floor, Kurt Austin puts the NUMA team on the case.

Kurt Austin, Joe Zavala, and members of the NUMA Special Assignments Team are called in to investigate after ships are destroyed near the Azores and they find themselves entangled in the ambitions of an African dictator who may have developed a weapon with extraordinary power.