The Rockhounds need an eleven-thousand-dollar miracle to turn their season around, Kirsty and Patrick urgently need to find rare Ocean Kyanite crystals to have any chance of recouping their huge debt while Kyle Archer strikes a monster $200,000 payday of Mookaite.

The Rockhounds hunt a tropical rainforest river system not far from crocodile-infested waters as Patrick and Kirsty return to the site they found their million-dollar Amethyst. Jarrin and Hugh confront low oxygen levels and crumbling mine walls.