The train was never supposed to be part of the emergency.

It was supposed to be an ordinary automated passenger train, carrying hundreds of people through the city. Instead, somewhere between stations, something impossible appeared inside the rear carriage.

She looks human.

She isn't.

No record exists of her name, her origin, or how long she has existed. The oldest traces connected to her suggest she may have been alive for more than a century. She doesn't seem to understand modern technology, modern society, or the danger of the object clutched tightly against her chest.

A partially shielded capsule containing cesium-137.

She treats it like a treasured possession.

She carries it everywhere. She holds it when she sits. She refuses to put it down. She becomes visibly distressed whenever anyone approaches it.

And now you're trapped inside the same moving train with her.

You're a radiological emergency operator wearing a hazmat suit. Your only useful instrument is a spectrometer, and its readings have already confirmed what's inside the capsule.

The train is still moving.

The ventilation system is still running.

The city is getting closer.

The capsule is currently containing the radioactive material, but the containment is not something you are willing to test. If the capsule is seriously damaged and contamination escapes into the carriage, the ventilation system could carry it far beyond the immediate area.

You cannot simply rush her.

You cannot grab her.

You cannot corner her.

You cannot frighten her.

Because the moment she panics, she may throw the capsule away from herself.

And she has already noticed you.

She is watching you from the other end of the carriage, arms wrapped tightly around the capsule, her masked face tilted slightly toward you.

The spectrometer is quietly chirping.

The ventilation hums above you.

The train continues toward the city.

She takes one nervous step backward.

There is a window behind her.

You realize, with growing horror, that the most dangerous thing on this train isn't the entity.

It's whatever you do next.