On a rainy afternoon at Primary School No. 7, Lena, Jakub, and Nikola find a glowing door hidden behind the lockers - and step into a place that should not exist.
Rain rattled hard against the windows of Primary School No. 7, and the corridor outside Lena's class had gone almost silent. Most of the students were still inside, but Lena, Jakub, and Nikola had been left on after-school duty, which meant gathering forgotten gloves, notebooks, and the odd scarf from the lockers and benches. Lena was perched on the windowsill, bored out of her mind, when the lights flickered and the air turned cold.
Behind locker number 14, a thin green line appeared where there had been nothing before. The line widened, stretched, and slowly became a door. Lena stared. So did Nikola, who tightened her grip on the locker key until her knuckles went white. Through the little frosted window in the door, something moved in the dark.
"Please tell me I'm imagining this," Nikola whispered.
Jakub, who never seemed to know when to stop, stepped forward and wrapped his fingers around the handle. Lena reached for his sleeve, but it was already too late. The door swung open with a soft creak, and a wash of light spilled into the corridor.
The space beyond was not another room in the school. Crystals floated in the air like glowing glass birds, and sparks shimmered in the distance, drifting through a strange silver mist. On the floor, letters blazed into view one after another: Choose your power. You have three minutes.
Lena felt her heartbeat thudding in her throat. She glanced at her friends just as each of them reached for a different crystal. The moment their fingertips touched the glass, green light burst outward, wrapping around them like lightning.
Lena gasped as her own hands began to fade.
A rustling sound rose behind them in the corridor. Something was moving fast. The door behind Lena started to shut, and in the narrowing gap she saw shadows sliding toward them across the floor.