Thirty-two weeks pregnant, I watched my husband walk into his family’s Christmas party with another woman wearing the diamond necklace he had secretly purchased during a hotel stay. Sixty guests were watching when I finally told him, “Since you brought someone, I brought someone too”—but Matthias had no idea that his infidelity was no longer the most dangerous secret I had uncovered.

Upstairs, the sound of glass breaking and people shouting echoed through the mansion.

Matthias came barreling back down the stairs, carrying four massive yellow boxes of industrial baking soda and a heavy steel wrench he had grabbed from the maintenance room. His tailored suit jacket was torn at the shoulder, and his face was slick with sweat.

"I got them!" Matthias gasped, handing the boxes to me.

"Use the wrench to loosen the intake valve on the duct!" I ordered.

Matthias slammed the wrench against the pipe bolts, leaning his entire body weight into it. With a loud CRACK, the steel bolts gave way, exposing the open air pipe leading directly into the vault. I immediately began tearing open the baking soda boxes, pouring the white powder down the pipe while mixing it with gallons of bottled water Arthur had rushed over from the storage rack.

The chemical reaction was instant. A loud fizzing sound echoed inside the ventilation shaft as the alkaline mixture neutralized the toxic chlorine gas drifting through the vault.

"David!" I yelled into the pipe. "Are you breathing?!"

A heavy, agonizing cough came back, but this time, it was stronger. "Yes... the smoke... it's clearing! But the heat... the bottom thermal relay just turned on!"

"The thermal charge," Arthur said, stepping back from the electrical panel, his hands covered in black grease. "I cut the main relays, but Richard installed an independent internal battery inside the vault walls. In ten minutes, the heat will ignite the paper archives."

Suddenly, heavy footsteps echoed from the top of the stone basement stairs.

We turned toward the light.

Standing at the top of the staircase was Richard Dre. He was no longer acting like the jovial patriarch or the refined billionaire. In his right hand, he held a sleek black remote control unit with a glowing red LED light at the tip.

Behind him stood Fiona Vale, looking terrified, flanked by two of Richard's private security guards.

"That's far enough, Matthias," Richard said, his voice cold, hollow, and utterly devoid of fatherly affection. "I didn't expect Serena to be quite so clever with high school chemistry, but it doesn't change the outcome."

Matthias stared up at his father, his eyes bloodshot. "Dad... David is in there! You locked David in the vault!"

Richard didn't even flinch. "David was weak, Matthias. He was sloppy. The federal investigators were already tracing his signature on the Boston pension transfers. If he lives, he talks. If he dies in a tragic electrical fire caused by his own unauthorized access to the vault, the investigation dies with him, and Dre Global collects a forty-million-dollar corporate insurance payout."

Matthias took a slow step up the stairs, his fists clenched so hard his knuckles turned white. "You used him. You used us all."

"I built an empire, Matthias!" Richard roared, his voice echoing in the cold basement. "An empire that funded your private schools, your luxury cars, your Manhattan penthouse, and that ridiculous thirty-thousand-dollar necklace you bought for your little mistress!"

Fiona shrank back, her face pale as death.

"I did what was necessary to protect the family name!" Richard continued, pointing the remote control at the basement ceiling. "Now step away from that door. In three minutes, the remote override will trigger the thermal collapse. The guests upstairs are already being evacuated through the front gates by my team. It will all look like a tragic accident."

"No," I said, stepping past Matthias to stand on the third step, looking up at my father-in-law.

Richard glared down at me with pure venom. "Get out of the way, Serena. You were always an outsider in this family. A schoolteacher's daughter who thought she could lecture us on morality."

"I might be a schoolteacher's daughter, Richard," I said, taking another step up toward him, holding my hand firmly over my stomach. "But you forgot one detail when you planned your perfect little corporate insurance scam tonight."