My mother-in-law screamed when my husband drank my wine at his sister's wedding, unaware I had secretly swapped the poisoned glass.

I waited two minutes before excusing myself to use the ladies' lounge. The heavy mahogany door of the bridal suite was half-ajar down the private gallery hall, past the velvet-roped corridor reserved for the wedding party.

As I approached the door on soundless satin heels, the muffled sounds of frantic, hushed sobbing reached my ears.

"You idiot! You clumsy, incompetent idiot!" Martha’s voice was a venomous whip, stripped entirely of its patrician melody. "Did you put it in the wrong glass?"

"I didn't! I swear to God I didn't, Mom!" Rebecca was weeping, the sounds smothered by thick fabric. "I did exactly what you told me! When Caroline went to the coat check before the processional, I slipped the vial into her glass at place setting four! Patrick was at place setting three! I know how to count to four, Mom!"

"Then why isn't he on the floor?" Martha shrieked in a furious whisper. "Why is he sitting out there asking for seconds of tenderloin while my heart is beating out of my chest? That dose was calculated for a woman of a hundred and twenty pounds! It causes ventricular tachycardia within four minutes! Patrick weighs one-ninety—even with his size, he should be convulsing!"

I stood in the shadows just outside the door frame, feeling an icy calm settle over my marrow.

Ventricular tachycardia. A heart attack. A sudden, tragic, unexplained cardiac arrest in a healthy twenty-seven-year-old woman. And because I had a known childhood history of a minor heart murmur—something I had stupidly shared with Martha over tea two years ago when we first got engaged—everyone would have thought it was a sad, unforeseen congenital failure.

They didn't just want me humiliated. They didn't just want Patrick to divorce me.

They wanted me dead.

"Mom, what if it has a delayed reaction?" Rebecca sobbed, her voice hitching hysterically. "What if he collapses during the first dance? What if we just killed my brother?"

"Shut up!" Martha snarled. A sharp crack echoed in the room—the distinct sound of an open-handed slap. Rebecca gasped into silence. "Pull yourself together! If Patrick dies, the coroner will find the aconite. Do you understand what that means? They will run a full panel on an heir to the Vance estate! If Caroline died, it was a tragedy. If Patrick dies, it’s a homicide investigation!"

I gently pushed the door open.

The brass hinges made no sound against the deep wool carpet. I stepped into the room, closing the door behind me with a decisive, heavy *click*.

Both women whipped their heads around.

Martha was gripping Rebecca’s bare shoulders, her manicured fingers digging into the satin of the wedding gown. Rebecca had a bright red handprint flaming across her left cheekbone, tears streaking her perfectly airbrushed foundation.

When Martha saw me standing there, tall, immaculate in my emerald gown, her breath left her in a sharp, wheezing hiss.

"You look distressed, Martha," I said, my voice smooth as melted glass. "Is something wrong with the wedding arrangements?"

Rebecca backed away from her mother until her spine hit the vanity mirror, knocking over a crystal bottle of perfume that shattered on the marble floor. The scent of tuberose and jasmine burst into the room, suffocating and sharp.

"Caroline," Martha said. She tried to smile, but her lips merely peeled back from her porcelain veneers in a rictus of sheer terror. "We were just... Rebecca had an emotional moment. The stress of the day."

"Of course," I said, taking two slow steps forward. I reached into my clutch, feeling the cold, hard glass of the small sample vial Michael had given me. I didn't take it out. I just kept my hand inside, letting the silhouette of my fingers press against the fabric. "It must be terribly stressful. Wondering when the poison is going to take effect."

Martha turned gray. "What did you say?"

"Aconite," I murmured, tilting my head. "Monkshood. Queen of poisons. It causes numbness in the limbs first, doesn't it? Then a severe burning in the chest, irregular pulse, convulsions, and respiratory paralysis. A terrible way to die, Martha. Especially for an only son."

Rebecca dropped to her knees among the shards of broken glass, completely breaking down. "I didn't want to do it! Caroline, please! She made me! She said you were going to ruin the family trust!"

"Shut your mouth, Rebecca!" Martha roared, her facade shattering entirely. She lunged toward me, her eyes bloodshot, her manicured nails curled like talons. "What did you do with the wine? Where is the real glass?"

I didn't flinch. I didn't step back. When Martha reached within arm's reach, I met her gaze with a dead, unblinking stare that made her freeze in her tracks.