My husband’s best friend crashed our proposal, grabbed my hair in front of both our families, and screamed that the engagement didn’t count because nobody had asked for her approval.

Marcus told me the story in fragments, as though the whole thing had broken into pieces and he could only pick up the sharpest ones.

Ten years earlier, he and Kate had been twenty-one. Kate's father had been drinking again, so Marcus had gone to her house to get her out. Lila, fifteen and furious at being left behind, had climbed into the back seat without either of them noticing. Kate was driving Marcus's car. They were arguing about whether she should leave town when the road curved along the river.

The car hit the guardrail. Lila was thrown against the rear door and died before the ambulance arrived.

“The police asked who was driving,” Marcus said. “I told them it was me.”

“Why?”

“Kate was barely conscious. Her father was outside the hospital screaming that he would kill her if she had wrecked his car. I thought I was protecting her.”

“You took the blame for killing a child.”

“I didn't kill her.”

“But you told everyone you did.”

He flinched. I had never seen Marcus flinch at my words before.

The next morning, I found Kate's key on our kitchen counter.

I had not brought it home. Marcus said he hadn't either. He stood in the doorway of our apartment, staring at it with the same hollow expression he had worn in the conservatory.

“She must have dropped it,” he said.

“It was on the fountain when we left.”

“Maybe she had another one.”

“Of our apartment?”

He didn't answer.

My phone rang. The screen showed an unknown number. I let it go to voicemail. A minute later, a message appeared.

“Congratulations, Nora. I hope the ring feels comfortable. Marcus always liked things that looked rare.”

Attached was a photograph of my hand resting on Marcus's chest as we slept. The room was dark, but the shape of our headboard was unmistakable.

I dropped the phone onto the counter.

“She was inside,” I said.

Marcus took the phone and went completely still.

“How long have you known she had a key?”

“I didn't know she still had one.”

“That's not what I asked.”

He looked down. “She had a key when we were roommates in college. I never asked for it back.”

“She has been in our bedroom.”

“I know.”

The answer came too quickly.

I stepped away from him. “You know?”

“Not this time. I mean, I knew she had been coming by the building. The super mentioned seeing her once.”

“And you didn't tell me.”

“I thought I could handle it.”

“You thought you could handle a woman entering our apartment while I was asleep?”

“She has been unstable since the accident.”

“That word is doing a lot of work for you.”

Marcus's jaw tightened. “What do you want me to say?”

“I want you to say that you let this happen because you are afraid of her.”

He looked at the floor.

I called the building manager and had the locks changed. Then I called the police. An officer named Ramirez took the photograph, wrote down the number, and asked whether Kate had threatened us directly.

“She says she has approval rights over my engagement,” I told him.

Officer Ramirez paused. “That is not a legal category.”

“I know.”

“But trespassing is. Keep every message. Don't delete anything. If she comes back, call us while she's there.”

After he left, Marcus stood by the window with his hands in his pockets.

“May fourteenth,” I said. “You still haven't told me why Kate thinks that night gives her control over you.”

“Because I promised her I would never leave.”

“You were twenty-one.”

“Lila died. Kate blamed herself for letting her get in the car. I blamed myself for lying. We were the only two people who knew the entire story.”

“You said you were driving.”

“I said I was driving because Kate was terrified.”

“And after that?”

He closed his eyes. “After that, she kept saying I belonged to her because I was the only person who understood what we'd done.”

“What did you do?”

“We kissed once.”

The room seemed to tilt.

“When?”

“At the hospital. After Lila died.”

“You and Kate were together.”

“No.”

“You kissed her.”

“She kissed me. I didn't stop her.”

“That is not the distinction you think it is.”

He looked at me then, and the raw regret in his face made my anger more painful, not less.

“She said if I left her, she'd tell the police I had been driving drunk. I wasn't drunk, but I had been in the car. I thought she would hurt herself. So I stayed close. I answered every call. I let her believe she was the most important person in my life.”

“Was she?”

“No.”

“Then why did you let her believe it?”

He had no answer that could survive the question.

That afternoon, Kate sent another message.

“You can change the locks, Nora. You can't change the promise.”

I stared at the words until they blurred. Then I opened a new folder on my computer and named it KATE MERCER.