Civilisation gave way to the jungle and, beyond that, rumble. Gunung Kerinci is Indonesia’s highest active volcano. My guide called himself Eddy; a short, lithe man who tottered under his backpack. Platitudes were exchanged. “You married?” he asked. “Nope,” I said. “You?” “Yes.” Having ruminated briefly, he added: “But I hate my wife.” And with that we set about our two-day hike up the volcano.

Rice, corn and strips of cinnamon bark were spread out by the road to dry in the hot sun. Verdant tea plantations gave way to a scruffy beard of jungle ringing the volcano, which gradually petered out to solidified lava flows.

A narrow path led through dense undergrowth. Monkeys howled. It was hot, sweaty work. Eddy said little except to answer my questions. Mostly we trekked in silence. Occasionally he would stop and indicate a plant, such as wild ginger or the rare pitcher plants unique to this area.

I was negotiating my way over a fallen tree when Eddy came rolling past me and down the slope. In a blur of red canvas, flying shoes and flailing arms, he narrowly missed dragging me with him. He picked himself up and brushed himself off, as though what had left me stunned was more of a routine skirmish than a dangerous tumble.

For the next four hours, the route steepened. We slowly passed the 3,000m (1,875ft) mark, above the tree-line, and arrived at our campsite. It was windy and cold.

After 30 minutes, we had a pitiful fire going. Eddy pulled out an unmarked bottle that I took to contain water. I was close to the fire, trying to absorb warmth, when half of the bottle’s contents were unleashed onto it, causing an explosion that could well have been seen from space.

Checking my eyebrows, I decided it was time for some liquor. I had smuggled along a quart of whiskey; an emergency supply for just such an occasion. Eddy soon retired to the tent, but not before another mistimed round of pyromania.

Four in the morning. In total darkness, we began to walk. Two pairs of gloves barely kept the warmth in, but protected my hands from the sharp, igneous rock. On the horizon an electrical storm cast eerie shadows over the solidified lava. The wind groaned. Thunder was disguised as volcano noise. My torch sputtered a low-battery light over a makeshift graveyard for the six lives once claimed here.

The volcano’s gut gaped like the mouth of a basking shark. Sulphurous gas emanated in plumes, accompanied by a cracking noise from the bottom of the crater that sounded like a pebble being thrown into a dry well.

The sun shinned up over the horizon, spilling a glorious orange light. Perched on the lip of the volcano, I realised that I no longer felt the cold. I gazed at the perfect simplicity of the earth’s processes.

Eventually we headed down. I could only hope that Eddy planned to walk and not roll back to the bottom.