Later that night, after the dinner had ended and the commissary had emptied, Sepha sat alone in her office and pulled up a document she had started 18 days earlier and never finished.

It was a death certificate.

The patient’s name was at the top.

The time of the bite was filled in.

The rest was blank.

She looked at it for a while.

Then she deleted it, opened a new file, and began to write a different document, the first paragraph of the paper that would be read on a thousand worlds.

It began.

The human patient was bitten by a skithro at the 11th hour of station morning, and 14 minutes later, he asked whether it was edible.

Eighteen months after Sepha deleted the death certificate, a girl named Vela arrived at Meridian Exchange carrying a sealed medical case and a question that nobody wanted to answer.

She was thirteen by the reckoning of her home world, thin as a railing, with gray patterned skin and two narrow eyes that tracked every movement in the crowded arrivals hall.

The case was nearly as large as her chest, and she held its handle with both hands despite the pain it caused.

The customs officer asked her why a child was transporting biological material across an interstellar border without a guardian.

Vela said that her mother had been her guardian until yesterday.

Then she asked to see Dr. Sepha Ilanorth.

The officer looked at the case, saw the emergency medical seal, and called station security.

By the time Sepha reached the arrivals hall, Vela was sitting on a metal bench beneath a poster celebrating the first year of universal skithra antivenom distribution.

The poster showed a smiling Liran nurse holding a glass cartridge under a caption that promised protection on every frontier.

Vela had positioned her case on the floor so that it covered the lower half of the advertisement.

Sepha noticed the deliberate placement before she noticed the blood on the girl’s left sleeve.

She knelt beside Vela and asked who had been hurt.

My mother, Vela replied.

Sepha looked at the emergency seal and asked whether the girl’s mother had been bitten.

Vela shook her head.

She was the person who made the medicine.

That was the first moment Sepha felt the old coldness behind her ribs, the sensation she had known when she believed Hamish Doyle was going to die on her examination table.