Carbon monoxide laden exhaust fumes pour suddenly into Cessna 172 VH-TLS's cabin. Hot, dizzy, confused and with a splitting headache, the pilot tries to land. Flying school manager Jan and their new instructor watch horrified as it dives into a paddock and explodes into flames.
For CFI Don and engineer Tommo, what seems pilot neglect doesn't add up. The pilot's fiancee, afraid what he called 'carrying for cash' is crime-related, blames sabotage.
Don and Tommo's search for answers leads into a web of menace, murder and violence; threatening phone calls; a warning on a cassette tape; cars forced off the road, one a fatality, one a narrow escape for Jan. Why does someone try to recover the cassette, smashing it in the attempt? What do the cryptic entries in Murray's diary mean?
Romance is budding for the instructor, and horseplay during a picnic for two at the lake has a totally unexpected outcome.
Don intercepts a vicious attempt to kidnap Jan but is unable to avert a second, and both Jan and the instructor are kidnapped and locked in a shed at a private airstrip. To secure their release unharmed, he agrees to fly to an outback airstrip and bring back two locked and sealed cases. Having solved the diary entries, he knows what they contain and why; but what begins as just discomfort for the kidnapped pair while they wait for his return suddenly becomes a night of terror. He returns to an explosive climax, a flight with a leaking fuel tank, a dead engine, an unlit runway and a race to land in the face of an approaching thunderstorm.
With the cassette repaired, its importance becomes obvious, and a showdown at a second outback airstrip exposes the ringleader. A necessary deal wraps up a case which brings a highly satisfying result for the group.
A final day holds surprises for Don but there's no way he'd change any of it.