A psychotic man pours a blinding chemical into the Harts' pool. Seconds after Jonathan dives in for his morning swim, he surfaces, screaming in pain. After Jonathan is rushed to the hospital, the unexplained attacks continue.

Combining business with pleasure, the Harts scuba dive off the coast of Largos, testing an innovative underwater camera for the Navy. Early afternoon, as the Harts stroll along the beach, the body of a Navy SEAL working on the project washes on shore.

Note: This episode aired 37 days after Robert Wagner's wife, Natalie Wood, drowned off Santa Catalina Island.