It was Lukas. He stopped and looked directly at Max. Then the mist swirled between them again. They were hidden from each other.

Max had never thought of himself as competitive. That had changed. He felt a powerful urge to beat Lukas. He checked his map and took a moment to orientate himself properly. He estimated that the cache was 250 metres north-west of his position. Although he and Lukas were approaching it from different angles, they had a similar distance to travel. It would all come down to speed.

Max surged forward. His ankle hurt and he tripped a couple of times as he pushed himself through the snow, and he cursed under his breath. But he kept moving. The mist cleared again and he caught sight of Lukas. His opponent was no faster than him, but he was certainly no slower. They were neck and neck.

His muscles ached. His lungs burned. Through a gap in the swirling mist he could see, up ahead, a red flag stuck in a snow mound. It was twenty, maybe thirty, metres away. As he advanced on the target, all he could hear was his breath and his fast-pumping heart. He could sense Lukas to his right, even though he couldn’t see him.

And then he could. He was five metres away, his head down, his face fierce. They raced up the snowy knoll to the flag. As they approached, they shoulder-barged each other. Neither boy was thrown off-course, however. They fell on the flag at precisely the same time, tumbling to the ground as they did so.

Max lay in the snow, catching his breath. Lukas stood up immediately, brushing himself down and muttering angrily under his breath. To the right of the flag was a post. The fingerprint sensor was attached to it. Lukas pressed his thumb to the screen and nodded in satisfaction. Max stood up too. He felt a little embarrassed by his sudden competitiveness. They were supposed to be racing an unknown time limit, not each other. He pressed his thumb to the sensor. A neon-green light scanned it.

‘So what kept you?’

Max blinked. It wasn’t Lukas who had asked the question. It was someone on the far side of the snowy mound. A female voice with an Irish accent. He and Lukas exchanged a look, then peered over the leeward side of the mound. Abby was sitting there. She looked quite comfortable, sitting cross-legged and eating a chocolate bar. She gave them a friendly little wave.

Max stared at her. He looked over his shoulder, then back at Abby. ‘You left after us,’ he said.

‘You’re a sharp one,’ she said. ‘Max, wasn’t it?’

‘But how did you get here so quickly?’ Lukas said

Abby put one finger to her lips, pretending to think hard. ‘Well, Lukas my friend, I guess that would be by moving faster.’

‘Where’s everyone else?’ Max asked, looking around.