In the Pacific Ocean a Silicon Valley magnate vacationing on his luxury motor yacht Carpe Diem stumbles across a floating island of pumice.

Two weeks later, their motor yacht returns to its home port in San Diego on autopilot — but when it arrives, nobody gets off.

Sam Reilly and his team are called in to investigate what happened on board Carpe Diem. But what at first appears to be a simple boating accident soon turns into a deadly game of international intrigue — sending America and Russia racing toward each other on an unavoidable collision course.