The track was born of greed. In the 1920s the highlands around Wau yielded gold, and the easiest way in was the path from Salamaua on the Huon Gulf, climbing steeply south into ridges that tumbled over one another without pause. Prospectors loaded packs, paid local carriers, and walked. They named the trail for the Black Cat Mine that waited at the end. Rain fell almost every afternoon. Rivers rose in minutes. The leeches came up through the bootlaces and down from the leaves, and in between the two feedings, the mosquitoes did their work. Flynn called it a rigorous march in constant fear of ambush. He was not exaggerating. The villages along the route spoke different languages, held old grievances, and did not always welcome strangers walking through with rifles and gold scales.

On 8 March 1942, the Japanese took Salamaua. Their plan for Port Moresby had already failed at sea in the Battle of the Coral Sea, and it would fail again over the Owen Stanley Range along the Kokoda Track. The Black Cat offered a third route. If Japanese forces could push up from Salamaua, take the Allied airfield at Wau, and break into the Markham Valley, Port Moresby would be flanked. Throughout 1942 and into 1943, Australians of the 17th Brigade under Major-General Stanley Savige held the trail while the independent companies 2/3rd, 2/5th and 2/7th filed up behind them. On 23 April, the Allies pushed back along the ridges and ran into the hills the soldiers called The Pimple and Observation Hill. The Japanese were dug in. Four aircraft strafed. The mortars came up. The attack failed.

The battle for The Pimple went on for three weeks, each day rolling into the next with the same weather and the same dead. Attacks on 7 May and 9 May met the same result. Then the Japanese came forward, surrounding the foremost Australian company and closing in. Relief did not arrive until the afternoon of 11 May. By that time the company had absorbed eight assaults from parts of two Japanese battalions, the men fighting on a muddy hilltop through rotting boots and low ammunition. The next day, with field guns finally hauled forward, the Australians took The Pimple. Meanwhile the 2/3rd was holding Bobdubi Ridge, so harassing the Japanese supply line that Savige had to rein them in. A real attack on Lae would not come until September. The Pimple had mattered only in the way every mud-soaked hill in this country mattered: it cost men, and it bought time.

After the war the trail sank back into the jungle, and by the twenty-first century it had acquired a second life as a trekking route for hikers who wanted something harder than Kokoda. Porters from villages along the route carried packs and cooked rice over the same slopes their grandfathers had carried gold up. It was hard work for small pay, and the work was not evenly distributed between villages. On 10 September 2013 a trekking expedition was ambushed by a group the local press called Rascals, a name used across Papua New Guinea for armed gangs. Two porters were killed in the attack; a third died later of his wounds. The international trekkers were largely spared. The attackers, it became clear, were settling an old grudge about which village the hiring should have come from. Four men were arrested, with police searching for two more suspects. The track closed. It has since reopened, sometimes, for the kind of hiker the guidebook had always warned about.

From the air, the Black Cat is invisible. The ridges rise out of the Huon Gulf and fold into the highlands around Wau in a dense green that reveals nothing of the gold shafts, the war graves, the rusted mortar rounds, the trekking camps, or the porters who still walk up and down with packs on their backs. The jungle closes over everything. The prospectors are gone. The Japanese and Australian soldiers are gone. The Errol Flynn who wrote about lying awake in fear is gone. But the leeches are still there, and the cassowary somewhere in the undergrowth, and somewhere else a village still remembering who got hired last season and who did not.