Tom Huth had a mission: To swim with his Princess Kaikilani under a jungle waterfall and feel young again. Along the way, he found lush enclaves blissfully free of the postcard fantasy. But where was that waterfall?

Dark tropical clouds squat over the rim of the Waipi'o Valley as we enter on foot from above. The opposite cliff, laced with waterfalls from a morning rain, is glowing like green velvet in the muted sunlight. Below, heavy surf is walloping a black-sand beach, and the valley floor is tiled with mirror-glinting squares of taro fields and lotus ponds.

A thousand feet deep, a mile across, six miles long, the Waipi'o Valley on the Big Island of Hawaii looks like the garden of creation. In the island's half-forgotten mythology, this is an ancient playground of gods and departed kings, of shark-men and dog-spirits. long ago, the god lono came here searching for a bride and found the lovely Kaikilani combing her hair in a breadfruit tree beside Hi'ilawe Falls. To this day, it is said, the ghosts of great chiefs—Marchers of the Night—emerge from portals to the land of the dead in torch-lit processions.

Now, as we descend, we see tin roofs, groves of banana plants, and a bright yellow leaf afloat in the current of Waipi'o Stream—a blissful-looking kayaker. The narrow road dropping into the valley is so precipitous and slick with wet vegetation that we can barely keep our footing. At the bottom we turn up-valley, and around a bend the legendary Hi'ilawe roars magnificently into view, a river of water pouring straight out of the clouds and falling a thousand feet before disappearing into the uplifted arms of the coconut palms.

This is the bountiful, emerald Hawaii that all of us envision—until we come to the islands and find out that the beach resorts are situated on the dry, desertlike leeward shores, protected by mountains from incoming storms. Most travelers, as it happens, are happy enough to lose themselves in the resorts" make-believe jungles and take day-trips to places like the Waipi'o Valley. But for my own first exploration of Hawaii, I wanted to skylark through real jungle, even if it meant trading in some sunshine. So I ended up choosing the wild windward coasts of the Big Island and Maui. And I wanted to bring along my own Princess Kaikilani, to swim with her under a waterfall and pretend that we were young again.

A muddy track leads out to Waipi'o Beach, between ferns and elephant-ear plants, past African tulips aflame with red blossoms, through groves of sinuous, witchy trees whose mossy trunks are engulfed with parasite vines. We come to a sign: warning—this road leads to dangerous conditions. Teasingly vague, like an Ashcroft admonition. Then we catch our first sight of the beach, and a feral pony prances through the scene.

In the late 1700s, when white men arrived in Hawaii, this valley was the center of Big Island culture, home to thousands of people. History tells about chiefs like King Umi, who united the island in the 1400s, and Kamehameha the Great, who met Captain Cook and later became the first chief to rule over all of Hawaii. But foreign diseases and turmoil decimated the population. Then an epic tidal wave in 1946 drove most people to higher ground. Here is a beach, though, to stir the passions—one mile in length, a rugged shelf of pockmarked lava rocks and charcoal sand, the ocean storming with big raggedy rollers that not even the natives ride. Behind the beach are stands of spidery casuarina trees with spooky silhouettes that could have been painted by Munch. To either side, headlands spill over with fresh waterfalls. I wade into the strong current where the river meets the sea, the wind whipping my shirt.