Rory and Oscar are forced to operate their dad's 20-ton drill rig for the first time. The entire Tarantos family is struck down by sickness as they struggle to find Opals on their massive claim. The Bushmen build a dangerous mine roof.

The Tarantos' excavator grinds to a halt at the bottom of their mine. The Cheals also face machinery failure as Rory busts their digger underground. The Bushmen's roof is on the edge of collapse.