We did not go blackwater rafting. The weather wasn’t right – too much rain, making underground water levels too high. Too dangerous, they said. We didn’t argue.

We went on a more sedate cave tour and learned about the geology of the area, which I will not bore you with. The caves, many of them undiscovered, or at least unexplored, lie all across the sheep country northwest of Taupo, a region green as Ireland and ornamented by limestone crags, plinths, shelves, and sinkholes, speckled with copses of coniferous podocarp trees – 60-meter rimus, I think, and the smaller totaras – and girt by flowering gorse. (We were informed that gorse – which is literally everywhere in New Zealand – was introduced by the Scottish. But then, most plants and animals here were introduced by settlers, be they Maori or white. It’s both the tragedy and the triumph of the place.) The cave systems are extensive – but “extensive” doesn’t capture their scope. They are immeasurable. Everywhere amid the rolling hills are the “tomos,” Maori for “holes,” where the limestone has worn down from the battering rain and emptied into an abyss. It is a spelunkers’ paradise, not least because of the extant chance of discovery and glory. Few places in the world still afford such a chance.

Our guide, Norm, is one of those rare guides who seem to take a genuine interest in his charges. He has a brother working for DOC (Department of Conservation) who used to tie himself to trees in protest, so Norm is interested in Lisa’s affiliation with Friends of the Earth. When we tell him we lived in Washington, D.C. (easier than telling people we lived in Riverdale, Md.), he launches into a political discussion.

“So, what did you think of the elections, eh?”

“Very interesting results,” we say.

“Sure. And how do you feel about that Bush?”

“Well …”

“He’s a right wanker, isn’t he?”

The van heaves with a group guffaw. Our little tour is joined by four Germans, two Kiwis (Norm making three), two Aussies and two Brits. A nice microcosm, decidedly left-leaning.

We are entranced by the caves. We see two. In the first are the famous glow worms. It is pitch black except for a million points of unblinking starlight overhead: the slender hanging luminescent threads of glow worms. Glow worms are actually maggots, but glow-maggots, Norm says, is not the best tourist draw. The glow worms spin straight blue filaments much like spider webs to catch prey: light gleams from the end of the threads: in places they are so concentrated they shed enough light to see dimly by.

In the second cave, which Norm and his colleagues helped preserve, we see the bones of a moa – an extinct giant flightless bird, sort of a cross between an emu and an ostrich – next to the remains of goats, cows and possums. They wander in and get lost in the pitch black and lay down to die. Moa have been dead and gone for 500 years.

Norm tells us an old trick: colored lights on cavern walls. Tour companies often use such lights to enhance tourists’ visual experience. Such chicanery.

Outside the scudding field of clouds has darkened: more rain. We get back to our car park and one pair of Germans, Bavarians if I recall, has accidentally left their van’s lights on. We give them a jump: a last good deed by Melba, who now must return to Auckland.

The next morning, bright and clear, we hit the road early and head north for New Zealand’s biggest metropolis. Still 10 days before we leave, but we’re worried about selling the car. The Backpackers’ Car Market is a capricious experience.