Martin Bayerle and his estranged son, Grant, go back to the wreck that nearly destroyed their family, and start an expedition which could be their last chance to solve the mystery of the RMS Republic and recover over a billion dollars of treasure.
Martin uncovers more of the mystery behind the Republic's treasure; during an attempt to recover the gold, a diver has an accident that puts his life in jeopardy and threatens to shut the mission down.
When the ship's generator fails, and diver Mark's condition worsens, the crew must head back to port; devastated Martin recalls his failed 1987 Republic dive and the crushing effect it had on his life.
Martin identifies a mysterious transaction with a Russian banker that may prove the gold is aboard the RMS Republic.
A diver gets tangled in the wreck and another line compromises the ship's propeller; Martin argues over the location of the gold chamber; the shooting that landed Martin in prison is finally revealed.
A dive on the port side of the wreck yields a piece of the past, and a suspicious boat is spotted nearby.
New information is revealed, and questions are answered about the history and mystery of the RMS Republic, her billion dollar gold cargo, and the Bayerle's obsessive quest to recover the bounty and unlock a century old conspiracy.
Grant challenges his father's strategy and attempts a new approach to recovering the bounty of the Republic.
The crew goes for the Republic's treasure, and faces down a destructive storm.