She had carried a medical alert card in her wallet ever since, and warned every physician she ever saw, and built her whole life around the avoidance of a single molecule.

There was no scenario in which a patch delivering that exact substance found its way onto her chest by chance.

None.

A patch like that does not fall from the sky.

It does not come free with a country-club membership.

Someone chose it, specifically, because of what it would do to her, specifically — and to know which substance would kill this woman, you had to be one of the very few people on earth who knew about her allergy at all.

I knew about it, because I had been the physician in the room, twenty years ago, when it nearly killed her the first time.