The steep, rutted track up which our taxi has been labouring for nearly an hour is now exceedingly narrow. We lurch to a halt as it dribbles out altogether.
Looking around, I notice two men stealing through the undergrowth with bamboo bows and arrows, naked but for their nambas; traditional penis gourds.
We're on the jungle-clad upper slopes of Vanuatu's Tanna island and we've come to meet the people who worship Prince Philip. Yes, Prince Philip - the Duke of Edinburgh.
Bizarre though it seems, the British Queen's husband is venerated in this corner of the Pacific, where locals believe he is descended from one of their ancestral spirits.
No one speaks English up here, so our taxi driver agrees to translate. Siko Nathuan, a tribal leader in the village of Yaohnanen, leads the way to a modest thatched hut that serves as a shrine.
Ducking inside, he emerges with a pile of newspaper cuttings about the Prince, then produces the villagers' most treasured possessions: three signed photographs, sent out by Buckingham Palace over the years.
Tribespeople in Yaohnanen and nearby villages are convinced that the 89-year-old Duke is from Tanna and that one day he will return to live among them. On learning that I'm British, Nathuan's face lights up.
"Can you tell Prince Philip we are waiting for him?" he asks.
He is deadly serious. And so are followers of other "cargo cults" that have sprung up on the island since Western missionaries arrived in the 19th century, and which still wield a powerful influence. In Namakara, in eastern Tanna, villagers worship a shadowy American figure whom they call John Frum, probably a legacy of the GIs stationed here during World War II.
Namakara is rather more accessible than Yaohnanen; it's not far from the White Sands resort. Visit in February and you'll be treated to a curious sight: men in GI-style uniforms, marching around a parade ground beneath a Stars and Stripes flag, wooden rifles aloft.
During the war, hundreds of men from Tanna were recruited to build roads and airstrips; the chief of Namakara, Isaac Wan, says that friendship ties between the island and the United States are still strong.
The origins of the Prince Philip cult are more murky; however, an Australian anthropologist, Kirk Huffman, believes they lie in an ancient story of a light-skinned figure who emerged from a volcano and then disappeared overseas - only to return in the shape of the Duke, who visited Vanuatu with Queen Elizabeth on the royal yacht Britannia in 1974.
That volcano, Yasur, is still active and is a popular day trip for visitors to Tanna.
A more offbeat destination is Latun, a traditional village where the locals still claim to practise black magic. Their cultural tour is highly enjoyable - it begins with a group of heavily painted "cannibals" leaping out of the bushes - but is also an opportunity to learn about the traditions of a bygone era.
In remote Yaohnanen, life goes on much as it did decades ago - although a mobile phone mast on a nearby hilltop hints at some differences. Children in ragged clothes play hide and seek among the giant banyan trees, and wild pigs are hunted with the bows and arrows we saw on our arrival.
In this spot, high above the resorts that attract divers and snorkellers, there is no electricity or running water.
No matter; chief Nathuan is sure Prince Philip will feel at home here when he returns.
The villagers have prepared a bamboo hut for the man they consider a god. It has a dirt floor, and a carefully tended garden.
"I know that in England he has a palace and servants," says Nathuan. "But here he will just live simply, like us."
The first framed portrait of the Duke - a black-and-white print, now damaged by mildew - was delivered to the people of Yaohnanen in 1978, after the British Resident Commissioner informed Buckingham Palace of the cult's existence. The second, which arrived a decade later, shows Prince Philip clutching a ceremonial pig-killing stick, a gift from the villagers. The most recent, a colour shot, dates from 2000.
Locals believe the Prince will bring the gift of eternal youth with him when he returns. There will be other gifts, too. Huffman, who has spent decades studying Tanna, wrote in the 1970s: "Mature kava plants will sprout all over the island ... there will be no more sickness and no more death ... a man will be able to take any woman he wants." As my companion observed: "It all sounds rather fun."
Getting there: Air Vanuatu has sale fares from Auckland to Port Vila starting from $589.32 return, and domestic connections to Tanna from A$253.20 return.
Where to stay: In Tanna, stay at the Evergreen Bungalows, from A$80 a night for a double or twin share.
The resort can book day tours to the Yasur volcano for A$89 per person and to Latun village for A$49 per person. To reach Yaohnanen, you have to travel under your own steam. It's best to book a taxi through the resort.
Further information: Visit vanuatutourism.com.
Kathy Marks paid her own way to Tanna.