The sand was as black as night beneath our feet and the wind-whipped waves roared like a taniwha as we made our way down the beach to the cliffs of hidden treasure. Our quest was for no ordinary riches. We were looking for something that no other human being had set eyes upon.
We had come to this lonely spot, on Kiritehere Beach on the wild west coast of north Taranaki, following the clues in a map sold to us by an ancient bearded man with black teeth, a wooden leg and a patch over one eye ... though I think he photocopied it from a brilliant little book called The Kiwi fossil hunters handbook.
As we approached the cliffs at the far end of the beach, we could see indications that other treasure hunters had been there before. Had they found all the loot already? Led by our two sons, aged 5 and 6 and both crazy about anything to do with dinosaurs, we searched feverishly, hoping against hope to find what we were looking for. And then, there it was.
From the outside it looked just like an ordinary rock shaped like a dinosaur egg. Armed with a special hammer, safety goggles and lots of excitement, the boys carefully chiselled away at the rock until, with a crack, it parted to reveal a collection of 200-million-year-old scallop-like shellfish called monotis. Anything edible was long gone. What remained was the shape of the animal's shell that had been turned into rock over many years. We had found our first fossil.
Although clams that lived at the same time as the dinosaurs were a pretty exciting discovery for my sons, other treasure hunters at Kiritehere have found greater riches, including the flat, spiralled shell of the ammonite (a relative of the nautilus) and the bones of a dolphin-like marine reptile (the ichthyosaur).
Of course, even the most enthusiastic dinosaur hunters need a few distractions and, fortunately, there were several other Xs marked on our treasure map, including spooky caves, secret waterfalls and giant fossilised oysters, which made for great little breaks on the return journey.
Our quest for treasure had started at the tiny seaside settlement of Mokau where we rented a bach perched on the cliffs looking down the coast to the snow-clad peak of Mt Taranaki.
At the spot where the Mokau River reached the sea, we spent many happy hours discovering the fossil of a scaphopod mollusc or tusk shell, semi-precious gemstones and geological oddities called concretions.
By the end of the expedition so many gems had been found that the captain complained the ship seemed to be lower in the water than when we had started.
But all the crew declared our adventure a huge success. We returned home with lots of treasure: new knowledge, amazing discoveries and precious memories.
* The Kiwi fossil hunters handbook by J Crampton and M Terezow (Random House, $39.99) is a great resource. As well as maps to help locate the treasure, the book includes photos to help identify your finds and heaps of information.
* There's more helpful information on the GNS Science website.
Accommodation: Try Book-a-bach.