Hi, I'm Natalie Morales.

Brigitte Uddo was a young mom in the prime of her life who showed up nearly dead in

an emergency room.

Her hair was falling out and her vital signs were fading.

It was a race against time for toxicologists and the FBI to solve not just this medical

mystery but a horrific crime.

This is also a story about the bonds of a mother and child and her will to survive and fight.

In my time with Brigitte at the very end, nothing short of inspirational.

But first, the mystery, the Prussian blue mystery.

From the moment the ambulance arrived at the San Diego emergency room in March 2018, the

situation was frightening and desperate.

Triage nurse Laura Comstock took one look at the young woman on the gurney and knew something

was terribly, terribly wrong.

She was losing her vision, she couldn't feel her extremities, her feet and her hands.

She couldn't even see the water that I was giving her.

The patient's name was Brigitte Uddo.

She had just turned 28, yet she seemed to be near death.

At that point, I mean, she was very, very strong.

She was probably the sickest patient in the ER at that time.

I had told my coworkers that you know she might code on me.

Whatever was killing Brigitte wasn't evident.

There were no bruises, no wounds, no obvious signs of infection.

...