Looking out the small window of the US Douglas C-47, 22-year-old Private Frank Casey watched the aircraft's wing vibrate and every now and again caught through the clouds glimpses of jungle-covered mountains. If they crashed, he thought, assuming they survived, ‘how in the name of Dickens’ would they find their way out of that ‘green hell’. The 15 men around him were members of the 2/6th Battalion. Some were veterans of the battalion's earlier campaigns in Libya and Greece in 1941. Others, like Casey, were reinforcements. Before boarding the aircraft in Port Moresby that morning, 14 January 1943, each man had checked his personal kit, cleaned and oiled his rifle, and picked up a bandolier with 50 rounds of ammunition. They also carried three days rations and two blankets. They would be living with only the most basic of amenities. After an hour's flying time, the C-47 touched down on the grass airstrip at Wau, a pre-war gold-mining settlement in New Guinea's Bulolo Valley. Casey was immediately struck by the area's natural beauty, describing it as ‘magnificent’.

After two nights at Wau, Casey's company set off to relieve a group of Australian commandos near Mubo. The company, 85 officers and men, were driven the first few kilometres to Crystal Creek. The rest of their journey was on foot along the Buisaval Track. They were expected to cover the 30 kilometres in three days. Even for fit men, the trek was slow and arduous. At times, they would march for 15 minutes and then have to rest for 15 minutes. All were exhausted when they reached their bivouac for the night.