Matt Hammond's boss and a government Senator decide to sack him after it appears that Matt has run their car off the road and threatened them. It transpires that Dr. Stark has hired an actor to impersonate Matt Hammond in order to discredit him, but the whole scheme backfires and Dr. Stark has to honour the promise of a $10,000 donation to Waratah National Park.

Matt Hammond is expecting a visit by a man to assist with blowing up an abandoned mine in Waratah National Park. The man turns out to be an old army buddy, Toby Boughton. Later, following an accidental detonation caused by a wombat, Matt and Toby are trapped in the mine which is slowly filling with water.

Matt's discovery of an abandoned sports car leads him into a violent encounter with the driver, a delusional war veteran who then takes Sonny hostage before stealing an airplane.