My brother leaned back in his chair with that familiar little smirk I had hated since childhood, looked across our crowded Thanksgiving table, and said, "Let's see if she's really allergic."

The change came so fast it seemed almost surreal.

Trevor set the spoon down with a clatter. His hand flew to his throat. His chin jerked upward, and a strange, wet rasp rattled in his chest.

"Trevor?" Paige asked, her laugh dying instantly. "Trevor, what's wrong?"

He couldn't answer.

His face turned a deep, terrifying shade of purple within seconds. His lips swelled, straining against his teeth, and his eyes bulged as he clawed frantically at the collar of his charcoal sweater. He tried to take a breath, but the sound that came out was a high-pitched, desperate whistle.

He was choking on his own airway.

"Oh my God!" Aunt Denise shrieked, knocking her wine glass over. Red liquid pooled across the white linen tablecloth like blood. "He's choking! Somebody help him! He's choking!"

My father bolted out of his chair, grabbing Trevor by the shoulders. "Trevor! Son! What is it?!"

"He isn't choking on food," I shouted, my instincts overriding the shock that had frozen the rest of the room. "He's having an anaphylactic reaction!"

"What?!" my mother screamed, trying to stand and wincing as her surgical knee buckled. "He isn't allergic to anything!"

"He is now," I said, running toward the entryway console where I kept my purse.

Trevor’s knees buckled. He hit the hardwood floor beside the dining table, knocking over two chairs. His hands twitched uselessly against his neck, his skin mottling into blotchy patches of blue and red. He was suffocating right in front of us.

Paige was screaming uncontrollably. My father was on his knees, weeping in total panic, trying to force Trevor's mouth open with his fingers.

"Move!" I yelled, dropping to my knees beside my brother.

I unzipped my handbag, pulled out my primary epinephrine auto-injector, and ripped off the safety cap. Trevor’s eyes rolled back; he was seconds away from losing consciousness entirely. I slammed the injector firmly into his outer thigh, right through his trousers, holding it firmly in place while counting three long seconds under my breath.

A sharp gasp tore through his chest as the epinephrine hit his bloodstream.

He didn't magically stand up—epinephrine buys time, it doesn't cure—but his airway opened just enough for a shuddering, ragged breath to enter his lungs.

"Call 911!" I screamed at Paige. "Tell them acute anaphylaxis! Now!"

Paige fumbled frantically with her phone, her hands shaking so violently she dropped it onto the rug.

Meanwhile, Trevor’s own phone—an expensive, flagship model—had fallen out of his sweater pocket during his collapse. It lay face-up on the floor, right next to my elbow.

The screen lit up with a loud chime.

It was unlocked.

A banner notification popped up from a contact saved simply as Aunt Denise.

The text message read:

Did she eat any yet? The server said two spoonfuls of the concentrate would guarantee an ER visit.

I froze.

My thumb hovered an inch above the glass. The epinephrine was still pumping through Trevor’s system, his chest heaving as my father rocked him back and forth on the floor.