6x15 - The Flying Doctors

Nick goes to an opal-miner called Jackson with a generator. Jackson attacks Nick but then get trouble breathing. He goes to hospital with his daughter while Nick stays to guard the mine. A thief comes at night and manages to get some opals with him. When Jacksom comes to the mine the following day he gets sick again and David take some tests of the mine. Jackson thinks his former partner, Palmer, stole the opals and goes over to his mine. David goes after him and finds them fighting in the mine. Suddenly the roof crashes down and the three of them are trapped inside. In the last minute they are saved by Tom and Nick. David finds out Jackson was allergic to some fungus in the mine and therfore he can't keep working in it. He sells the mine to Parker.