The moment they crossed the threshold, reality folded in on itself like origami made of light and shadow. Polly felt her feathers stand on end as they passed through what felt like a curtain of static electricity, and then—
Winter.
The contrast was so jarring that Astrid gasped, her breath forming clouds in air that had dropped forty degrees in an instant. Snow crunched beneath her running shoes, and overhead, a full moon blazed in a star-studded sky that shouldn't have existed in Tromsø's June.
"This is impossible," she whispered, wrapping her arms around herself. Her running gear, perfect for the mild midnight sun marathon, was woefully inadequate here.
Polly fluffed her feathers against the cold, scanning their surroundings. They stood in a forest that was both familiar and alien—the same birches and pines, but skeletal and frost-covered, their branches heavy with snow. The entranced runners were visible ahead, still moving in that eerie synchronization, apparently unaffected by the dramatic temperature change.
"Look at them," Astrid said through chattering teeth. "They're not even shivering."
It was true. Mikkel and the others walked through the snow as if it were summer grass, their faces still blank, still focused on something in the distance that only they could see.
"Whatever's controlling them must be protecting them from the cold," Polly observed. She launched herself from Astrid's shoulder, flying ahead to scout. "Otherwise they'd have hypothermia within minutes."
The moonlit forest seemed to go on forever, but Polly's sharp eyes caught something glinting through the trees—a structure that definitely hadn't existed in the summer forest. She circled back to Astrid, who had started jogging in place to generate warmth.
"There's another bunker ahead. Bigger than the one we entered. And..." she paused, trying to process what she'd seen, "it looks new. Like it was just built."
"Or like we've gone back to when it was built," Astrid said grimly. "My grandmother said the experiments were conducted in 1943. What if this isn't just another place, but another time?"
Before Polly could respond, a new sound cut through the winter night—mechanical, rhythmic, growing closer. Searchlights suddenly blazed through the trees, and voices shouted in German.
"Hide!" Polly hissed, and Astrid dove behind a snow-covered boulder just as a patrol emerged from the forest.
Soldiers. Wehrmacht soldiers, exactly as they would have appeared in 1943, down to their grey-green uniforms and distinctive helmets. They marched past the entranced runners without giving them a second glance, as if people in modern athletic wear were perfectly normal in their wartime forest.
"They can't see them," Astrid breathed. "The runners exist here, but not for them."
Polly's mind raced. "Different temporal phases. The runners are here but not fully here. That's why they're protected from the cold—they're not entirely in this timeline."
"But we are," Astrid said, her voice tight. "Which means we're visible to those soldiers, and we're definitely feeling this cold."
The patrol passed, their lights fading into the distance. Astrid emerged from hiding, her lips beginning to turn blue. They needed to move fast.
"The failsafe has to be in that bunker," Polly said. "But how do we get past whatever security they had in 1943?"
"We follow the runners," Astrid decided. "If the soldiers can't see them, maybe whatever's protecting them will extend to us if we stay close."
It was a desperate plan, but the alternative was freezing to death in a winter that had ended eighty years ago. They hurried after the entranced athletes, Astrid's marathon training serving her well despite the snow and cold.
The new bunker loomed before them—a massive concrete structure bristling with antennae and strange geometric symbols. The entranced runners were filing through its main entrance, where two guards stood at attention, their eyes focused on nothing.
"They're entranced too," Polly realized. "Whatever's calling the modern runners affected the soldiers as well."
They slipped past the motionless guards, entering a corridor lit by humming fluorescent lights that seemed anachronistic for 1943. The walls were covered in equations and diagrams that hurt to look at directly, as if the mathematics themselves were trying to bend reality.
"There," Astrid pointed to a door marked with warnings in German and that same geometric symbol. "That has to be it."
But as they approached, Mikkel suddenly broke from the group of entranced runners. His eyes were still blank, but his movements became purposeful. He walked directly to a control panel and began entering a complex sequence, his fingers moving with inhuman precision.
"He's activating something," Polly said urgently.
The humming that had drawn the runners intensified, and the walls themselves began to vibrate. Through the windows, they could see the winter forest flickering, alternating with glimpses of the summer marathon route.
"The portal's destabilizing," Astrid said. "If it collapses while we're here—"
"We'll be trapped in 1943," Polly finished. "We need to stop him."
But as Astrid reached for Mikkel, his head turned toward them. His eyes were no longer blank—they swirled with the same impossible geometry as the symbols on the walls.
"You should not have come," he said, but it wasn't his voice. It was older, colder, and spoke with the weight of decades. "The experiment must be completed. Summer and winter, present and past, all must become one. The eternal day requires the eternal night."
"Who are you?" Polly demanded.
"I am the first success," the voice said through Mikkel. "Trapped between times since 1943, waiting for the right conditions to return. The midnight sun marathon, hundreds of runners generating electromagnetic fields through exertion, the perfect aurora forecast—everything aligned to reopen what was closed."
The truth hit them like the winter wind—this wasn't about the entranced runners at all. They were just batteries, their collective energy being used to power something far more ambitious.
"You're trying to merge the timelines," Astrid said, her scientific mind making the connection. "Create a place where past and present exist simultaneously."
"Where those lost in time can return," the voice confirmed. "Where the experiments can be completed. Where the eternal day never ends because it exists in all times at once."
The bunker shook violently. Through the windows, they could see both forests now, superimposed like a double exposure. The entranced runners stood at the intersection of both realities, their forms flickering between summer and winter gear.
Time was running out in more ways than one.
