A distress signal is thought to be a hoax; Chris attempts to save the victims of a boating accident.

Tom and Delaney must apprehend a man before he destroys a sunken U-boat from World War II.

Holly's friend disappears while on a scuba trip on Gus' boat.

Tom and Delaney intervene when Chris falls in with the wrong crowd.

Cap has a run-in with a salvage operator who cuts loose boats from their moorings.

Flipper tries to free a pregnant dolphin from the Institute; Tom's niece becomes involved with a drifter.

Delaney's old friend unexpectly arrives seeking a place to hide.

A renowned documentary filmmaker comes to Bal Harbor to film the damage caused by drift nets, and she uses unscrupulous methods to get what she wants.

Alex faces a shark head-on to save someone's life.

A woman's search for the truth about her father's death unveils a secret the Navy's been keeping for a long time.