A distress call from a nearby freighter in the Caribbean brings a NUMA training mission to an abrupt halt. Leaping into action, Kurt Austin and Joe Zavala locate the damaged vessel, where they make an eerie discovery. The captain lies face down and clutched beneath him - an empty shotgun. When Kurt and Joe search for clues, the situation grows stranger - and more dangerous. Lying hidden in wait are the rest of the crew: paranoid, disoriented and ready to fight. Could a mind-altering sickness have struck down an entire ship? Or is something much more sinister going on? Following the crew's tale of mysterious lights leads Kurt and Joe to a cadre of Cuban mercenaries, and when they learn of their plan to use magnificent modern airships to hijack a nuclear submarine, this impromptu mission moves from the seas to the skies. Faced with an irrepressible enemy and a new arena of fighting, stopping this plot could be the NUMA crew's toughest task yet...