A diver gets entangled in the wreck, while a line compromises the ship propeller. Later, Tim dives into harm's way; Martin quarrels over the gold-chamber location; and the shooting that put Martin in prison is revealed.
The ship's generator fails and diver Mark's condition takes a turn for the worse, forcing the crew to head back to port. Meanwhile, Martin remembers a failed dive and the crushing impact it had on him.
Father and son treasure hunters explore the sunken cruise liner RMS Republic. In the opener, Martin Bayerle and his son, Grant, try to solve the mystery of the Republic and attempt to recover over a billion dollars of treasure.