With Rod away on urgent Mines Department business, leaving Les in charge, Sam and Ben battle a dangerously steep ramp underground. It’s the last dig of the season and Dan and Renee are fighting ultra hard rock in a hail Mary search for opal at Benito’s... After a season-long battle against an unyielding rock cap, The Mooka Boys are finally ready to start tunnelling toward black opal glory, until their last working machine suffers a catastrophic breakdown.