In a small town, at High School #17, an open class on safety was being held. Students, teachers, and parents filled the auditorium, curious to see the demonstration. On stage appeared a uniformed officer alongside his partner—a German Shepherd named Rex—walking calmly at his side.

At first glance, Rex seemed relaxed, almost lazy, but his sharp eyes scanned every face in the crowd. The students whispered and giggled. The officer smiled proudly and said:
— “He’s not just a dog. He’s my partner. And he never makes a mistake.”

The demonstration began. Under the officer’s command, Rex found a replica firearm hidden in a backpack and then a marker tucked in a volunteer’s pocket. The audience applauded, amazed at his precision.

But just as the presentation was about to end, something changed. Rex’s body tensed, the fur on his neck bristled, and his gaze locked on the crowd. Suddenly, he lunged forward, growling.

— “Rex, stay!” —the officer shouted, but the dog didn’t obey.

Rex leapt toward a girl in the third row. Her name was Mary, a shy and quiet student. He knocked her to the ground, her notebook tumbling beside her. The auditorium erupted in screams. Teachers rushed to help, and the officer, holding the leash, muttered in surprise:
— “He never acts without a reason… never.”

Mary trembled, crying. Many assumed it was a mistake, but the officer wasn’t convinced.
— “Miss,” he said sternly, “I need you to come to the station with your parents. It’s just a procedure.”

The parents protested, but Rex continued growling, never taking his eyes off the girl. His instincts were telling him something more.

At the police station, Mary’s fingerprints were taken. Minutes later, the system triggered an alert. The officers froze.

The prints belonged to a person listed in the federal database of wanted criminals.

The officer looked at her coldly:
— “Do you want to explain yourself, or should I read your file?”

Mary took a deep breath. Her expression changed completely: the scared girl disappeared, replaced by a woman with a firm, unwavering gaze.
— “Fine,” she said calmly. “The game is over.”

Her real name was Anna. She wasn’t sixteen, but thirty. A rare disorder had prevented her body from aging, giving her the appearance of a teenager.

She had been on the run from the law for years. She had committed thefts, frauds, and jewelry heists, always escaping without leaving a trace—because no one suspected a “student.”

She changed schools and names, pretending to be an orphan taken in by various families.
— “No one would have guessed,” she smiled. “If it weren’t for that stubborn dog, I’d still be free.”

The officer looked at her calmly.
— “People can lie, Anna. But Rex… never makes a mistake.”