The late October sun streamed through the large windows of Marie’s apartment, painting warm rectangles on the hardwood floor. It was one of those rare days in Berlin when autumn hid its ugly face and instead showed off with golden colors and clear air. Marie Schäfer sat cross-legged on her couch, laptop on her knees and a cup of coffee within reach on the low coffee table. She had taken the day off—a rarity in her hectic life as an art director.

“It won’t get better than this,” she murmured, clicking “Save.” The presentation for the cosmetics manufacturer was finally finished, three days before the actual deadline. Marie stretched and allowed herself a moment of satisfaction. Perhaps it wasn’t the most exciting Friday, but after weeks without a day off, this self-granted vacation day felt like pure luxury.

She closed her laptop and stood up. The apartment in Prenzlauer Berg was her sanctuary, her fortress of silence amidst the noisy city. After breaking up with Markus a year ago, she had left their shared apartment in Kreuzberg and moved here—a fresh start that still felt somewhat temporary, even though almost all the boxes had been unpacked by now.

Marie went to the kitchen, rinsed her coffee cup, and checked the time. Just after one. The rest of the day belonged to her. She could go to the cinema, or simply stroll through the streets, perhaps stop at one of the cafés and watch people…

The ringing of her phone interrupted her thoughts. The number on the display was blocked. Marie hesitated. Normally she didn’t answer such calls—too often they were telemarketers or surveys. But today, in her relaxed mood, she pressed “Accept.”

“Hello?”

Silence on the other end of the line. Then a strange clicking, like a mechanical timer.

“Hello? Who is this?” Marie asked again, this time with a trace of impatience in her voice.

“Ten minutes,” said a voice. It sounded distorted, artificially deep, obviously filtered through a voice changer. “You have ten minutes to leave your apartment. If you’re still there after that, you will die.”

Marie snorted and shook her head. “Are you serious? Who is this?”

“Nine minutes and fifty seconds,” the voice replied monotonously. “Nine minutes and forty-nine seconds…”

“Listen, I don’t know who you are or what this is about, but—”

“Nine minutes and forty-five seconds. Tick-tock, Marie.”

A cold shiver ran down her back. The caller knew her name.

“Who are you? What do you want from me?” Her voice sounded sharper now, the hint of amusement gone.

“Nine minutes and forty seconds.”

The connection was cut.

Marie stared at her phone. A joke, she thought immediately. A stupid, tasteless joke. Probably one of her colleagues from the agency. Thomas perhaps, the technical director who had a strange sense of humor. Or maybe Claudia, the new graphic designer who was always trying to make her mark with silly pranks.

Marie put the phone on the kitchen counter and took a deep breath. There was no reason for concern. Nevertheless, she felt her heartbeat accelerate, felt a slight uneasiness creeping into her stomach.

Ridiculous, she thought. Don’t let yourself be intimidated.

Marie went back to the living room and sat down on the couch again. She picked up her tablet from the table and unlocked it, trying to distract herself from the strange call. The homepage of her favorite newspaper loaded, headlines about politics and celebrity dramas flickered across the screen, but she couldn’t concentrate. Her thoughts kept wandering back to the call.

Eight minutes and twenty seconds, whispered a voice in her head.

Marie glanced at the apartment door. It was double-locked, as always. The windows were closed. She lived on the fourth floor, without a balcony. No one could just come in.

And yet…

The caller knew her name.

Seven minutes and fifty seconds.

Marie got up and went to the window. Below on the street, the normal life of the neighborhood pulsated. A mother pushed a stroller in front of her, two businessmen talked gesticulating at the corner, a bicycle courier whizzed by. Everything normal. Nobody staring up at her. No suspicious vehicle parked across the street.

She went back to the couch and reached for her phone to call Lucas, a colleague she got along well with. He would know if someone at the agency was behind this prank.

The phone rang, but no one answered. After the fifth ring, the voicemail picked up. Marie hung up without leaving a message. What would she have said anyway? Hey, I just got a weird call, and now I’m scared? Ridiculous.

Six minutes and thirty seconds.

“Stop it,” Marie said loudly into the empty room. She was annoyed with herself. How could she fall for such an obvious prank? She was 34 years old, not an easily frightened teenager.

A soft beep made her perk up.

The smoke detector.

Marie looked up at the ceiling where the small white device was mounted. It beeped again, short and quiet, barely audible. Not the piercing alarm that sounded when smoke was actually detected, but the warning signal of a weak battery.

Odd coincidence, thought Marie, trying to ignore the uneasy feeling rising within her. The smoke detector had only been installed three months ago, when she moved in. The battery should last much longer.

She got a chair from the kitchen and placed it under the smoke detector. As she climbed up and examined the device more closely, she paused. The casing looked different than she remembered. Slightly narrower, with a small red LED she had never noticed before.

With trembling fingers, she opened the cover of the smoke detector. Inside was not only the usual electronics but also a small black box that definitely didn’t belong there. It was attached with thin adhesive tape, and a tiny red light blinked at one-second intervals.

Marie hastily climbed down from the chair and backed away as if she’d been burned. This was no ordinary smoke detector anymore. Someone had tampered with it. Someone had been in her apartment.

Five minutes.

Panic rose within her, a biting feeling that constricted her throat. Marie rushed to the bedroom and yanked open the drawers of her nightstand. Had someone changed something here too? She frantically searched the wardrobe, glanced under the bed. Nothing unusual.

Back in the living room, she stood still and tried to think logically. If someone had tampered with the smoke detector, what did that mean? Was it really possible that the threat was genuine? But why? Who would want to harm her?

The countdown in her head ticked relentlessly. Four minutes and twenty seconds.

Marie grabbed her phone and dialed emergency. As she held the phone to her ear, she hesitated. What would she say? That an unknown caller had threatened her and she had found a strange object in her smoke detector? Would the police take it seriously? Would they arrive in time?

Four minutes.

She hung up before anyone could answer. There was no time for explanations. If the threat was real, she had to leave the apartment immediately.

Marie put her phone in her pocket, grabbed her wallet and keys from the sideboard, and ran to the door. Her hand was already on the doorknob when she paused.

What if that was exactly the goal? To lure her out of the apartment? Maybe someone was waiting for her outside?

Three minutes and forty seconds.

She shook her head to dispel the thoughts. No, it was obviously more dangerous to stay in the apartment. She had to get out, and quickly.

Marie opened the door and stepped into the hallway. The silence of the stairwell enveloped her, only the quiet hum of the neon tube on the ceiling could be heard. She closed the door behind her and listened. No unusual sound, no footsteps, no whispering.

Slowly she moved toward the stairs. Her instinct told her to avoid the elevator—too slow, too risky if someone was really waiting for her. She began to descend the steps, taking two at a time, her footsteps echoing in the stairwell.

Three minutes.

She stopped on the third floor. Should she ring one of the neighbors’ doorbells? Mrs. Becker in 3B had always been friendly to her. But Marie hesitated—what if she put the neighbor in danger? If the threat was real, she wouldn’t want to involve anyone else.

She continued her way down, now a bit slower, all senses heightened. As she reached the second floor, she heard a door opening above her. Marie froze and looked up. A young woman with a stroller appeared on the landing of the third floor. The neighbor from 3A, whom Marie only knew by sight.

The presence of another person—and with a small child at that—brought Marie back to reality. What was she doing here anyway? Fleeing from an anonymous call and a tampered smoke detector? It sounded so absurd, so paranoid.

Two minutes and thirty seconds.

Marie forced herself to keep going. Better paranoid than dead, if the threat was indeed real. On the first floor, a door opened, and an elderly man stepped into the hallway. Mr. Kleinschmidt, the retiree who lived on the ground floor and walked his dachshund every morning at six. He nodded to her kindly.

“Good day, Ms. Schäfer,” he greeted her with his raspy voice.

“Good day,” Marie responded automatically and continued on, trying not to give the impression that she was fleeing.

When she reached the ground floor, she hesitated again. The glass door to the courtyard was right in front of her, but it led to an enclosed area with only one exit. If someone was waiting for her, she would be trapped there. The main entrance at the front was busier, leading directly to the street.

Two minutes.

Marie opted for the main entrance. With quick steps, she walked through the hallway to the front door, opened it, and stepped out into the autumn sunshine. The fresh air hit her like a blow, and suddenly she felt foolish. There was the normal world, the street, people passing by without giving her a second glance. How could she have let herself be so intimidated by a threat?

She stood on the sidewalk, unsure what to do next. Go back? No, that still seemed too risky. Go to a café and wait there? That sounded reasonable.

Marie glanced at her wristwatch. One minute and thirty seconds.

She began walking down the street, toward the small Italian café on the corner. Her thoughts were racing. Who could be behind all this? She had no enemies, no bitter ex-lovers, no professional rivals who would resort to such extremes. The only thing she had done lately was work on the new cosmetics campaign for a major client. But that was nothing that would prompt someone to make a death threat.

One minute.

Marie walked faster, almost running now. The café came into view, an inviting place with small tables on the sidewalk and warm light behind the windows. She would go in there, order a coffee, and call the police. In public, she would be safe.

Thirty seconds.

As she reached the door of the café, she turned around once more and looked back at her apartment building. From the outside, everything looked normal, peaceful even. The sun reflected in the windows of the fourth floor, where her apartment was located.

Ten seconds.

Marie opened the door of the café, the smell of freshly ground coffee and pastries greeting her. She entered, chose a table by the window, and sat down, her eyes still fixed on the apartment building.

Five seconds.

She took out her phone, ready to finally call the police.

Three… two… one…

The explosion was deafening. Marie watched as the windows of her apartment shattered in a bright flash of light, glass shards and debris raining down onto the street. A pillar of fire shot from the windows, followed by a dense black cloud of smoke. People screamed, ran away, or stood frozen in place. Car alarms wailed.

Marie sat petrified. Her apartment. Her things. Her life. All exploded, gone up in flames. And she would have been right in the middle of it, if not for the call. The call that had saved her life.

But why had someone warned her? Who wanted to kill her and save her at the same time?

A second phone in her bag vibrated—an old model she used as a backup and had almost forgotten about. With trembling hands, she pulled it out. A new message from an unknown number:

“Well done, Marie. That was just the first test. We’ll see each other soon.”

Sirens wailed in the distance as Marie stared at the message, her face pale in the reflection of the flames shooting from her apartment. Ten minutes had been enough to change her life forever.