The final bell rang down the corridor as loudly as if the school was trying to drive all the students out. Lena, however, didn't feel like leaving - her instinct told her to turn back to the empty, long unused wing of the building. Hardly anyone looked in there. The shabby walls and worn-out benches were a reminder of the days when the school was full of children. Now the place was silent, broken only by the tapping of rain against the rusty window sills. Lena had never been afraid of being alone, but today she felt something else - anxiety, mixed with excitement. For the past few days she had had the feeling that the world around her was changing. It started when her reflection in the mirror seemed to blink at a different time from her. Later, when she looked into the glass of the library, she saw not herself, but a boy with a scar on his cheek. The strange thing was that she recognised him - even though she had never seen him before. Today, Lena had come especially to a deserted classroom where an old, foggy mirror hung above the marble washbasin. As she faced it, her heart sped up. For a moment she saw her own face in the reflection, full of tension. Then everything changed. On the other side of the mirror, a scene was unfolding: a boy with a scar was running through a dark, narrow corridor, with a figure in a white coat chasing after him. Lena could feel their fear and feverish thoughts as if they were her own. Suddenly, the figure in the white coat turned and looked straight at Lena - through the glass, through time and space. In the same instant, cracks appeared on the mirror and the room around Lena trembled. The girl wanted to step back, but something wouldn't let her go. In the mirror she saw an inscription: "You have opened the door. Now you must enter..." A quiet rustling of footsteps came from the corridor. Someone or something was approaching faster and faster, and Lena still couldn't take her eyes off the illuminated reflection....