The throat of a Javanese volcano cannot be reached without huge physical effort. In my case, that means by using my legs and arms and risking some chance of disfiguration. I had already stumbled 4,000 feet up Mount Sibayak in Sumatra where, to our whole family’s dismay, we were greeted by a puny fissure pocked with trash, “I love LILA” symbols and whiffs of sulfurous smoke–but no signs of ejecta. I had hoped it would be the last of our volcano field trips–good riddance! But with finer judgments I am often wrong. As Charlie informed us on our nine-hour train journey from Jakarta to Jogjakarta, which took us past rice paddies and lovely verdant hills, a visit to a volcano does not count unless it spews molten ejecta within our sight and–holy of holies–within our range of its superheated temperatures. Suddenly I envisioned us wearing baggy silver asbestos suits with protective hoods over our heads.

There are some 220 active volcanoes on this Indonesian archipelago; many hundreds of others are thought to be extinct. The most famous, Krakatoa, west of Java, decapitated itself in 1883 with a blast that was said to be heard as far away as Australia. It darkened skies and set in motion a huge tidal wave that killed nearly 70,000 people. Today, the greatest concentration of active volcanoes with recent eruptions lies in Central Java. The most active (indeed, one of the world’s five most active) is Mount Merapi, which vents ejecta, superheated ash, and steam every 15 minutes on average. Guess which one we were heading for?

Charlie had made the arrangements, keeping the fact that our appointment with our volcano guide required us to wake up at 1:30 a.m.–a big surprise. Now, I used to go to bed at that hour as a younger man, but I do not recall ever getting up that early, except lately with gas. At the sound of the wake-up call, we turned out grumbling and stumbled into a taxi for a drive through the humid darkness toward our date with Merapi.

Our guide, Christian Awuy, 55, was waiting for us in crisp army fatigues and boots, a pea-green B-52 jacket, and a blue naval cap with gold embroidered “scrambled eggs” on its visor. A former second officer in the merchant marine, he wore the dour expression of someone who had three ships sink under him. Figuring himself three times lucky, he abandoned ships for volcanoes in the 1980s and now serves as secretary of the Mount Merapi Mountain Rescue Squad.

“The government does not like very much people climbing up volcanoes,” he told us in the dim light of his “briefing room.” He spoke English in a flat voice. “If I tell you to run–the speed of lava is 200 kilometers per hour–run very fast.” I think he caught my expression. “We watch lava from a safe place–so far.” The next part was news to me. “On the way up through the jungle, if you see the giant spiders,” he said as he opened his hand and spread out his fingers to indicate their size, “they are very sensitive but not poisonous.”

“They just get in your hair,” Charlie said, under her breath.

I liked the sound of this less and less, but when Christian handed us flashlights, which would guide our stumble along a Javanese jungle trail in the pitch dark, I liked it even less. Christian excused himself, saying he needed to make a telephone call.

“Are you kidding?” I whispered to Charlie.

“We have to go in the dark or we won’t be able to see the lava.”

Christian returned to the room. “The volcanologist I just spoke to on the telephone is warning that the volcano may erupt. There is to be an emergency meeting of the Rescue Squad in two hours. You will go with another guide.” He was straight-faced; this was a man who was not friendly with humor.

At that moment I was busy looking at the charts and other material posted on the walls of the briefing room. “During the eruption on Nov. 22, 1994,” one said, “Mount Merapi killed 69 people and the surrounding villages were evacuated for several weeks. So please don’t try to enter those places above mentioned in the Forbidden Zone. According to experts, Mount Merapi could erupt high scale anytime these days.”

I looked at Christian. “Is this true?”

“The people who died came from the village of Turgo. I warned them to leave. But there was a wedding party going on at the time. They said the lava had flowed the other way for 400 years, and what was different about now?” He shrugged his shoulders.

As we set out into the night, we blundered through the jungle. A few times I shined my flashlight into voids that I was thankful the beam couldn’t penetrate. Fraser walked ahead of me with an automatic ease, and Molly kept up like a trooper. After two hours of aggressive trekking, our guide told us we’d go no further.

We could see nothing in the dark. A far off rumble reached our ears. Our guide did not tell us where to look. Ejecta like sputum came out of Morapi’s gorge. With the force of gravity it spilled down a ridge at 90 degrees while we squatted in the brush. The Javanese dawn peeked through the gloaming. There was another burst of ejecta and then the mountain inexplicably went quiet as the sun rose higher on its beautiful symmetrical cone in dreamlike splendor.

“I suppose it’s better to have it this way, rather than the lava chasing us down,” Charlie said, but I heard disappointment in her voice.

Had it been for naught? I did not think so. It was an adventure we would not have had unless Charlie had goaded us on. We did encounter one giant spider, although it was in daylight, and our guide had not been forced to ask us to outrun liquid magma. Those were positive elements to build a new day on. We had seen ejecta. The imagination easily supplied the rest. But Charlie was thinking a different thought, I could tell. Once back at the hotel she buried her nose in the Indonesia guidebook.

“Ummmm,” she said to no one special. “There are two volcanoes on Bali.”

Molly, Fraser and I looked meaningfully at each other. Bali was our next stop.