Dr. Randall lets out an even breath, but he doesn’t say anything.

I stretch my legs out. They don’t hit anything, only air. “And I told her the lip gloss looked ugly, okay? I told her that. It was a mean thing to say. And it’s the last thing I ever said to my sister. Are you happy now?”

He shakes his head a little. “I’m not happy. But I’m glad you told me. I can see this is bringing you a lot of pain. It’s a very common occurrence that we regret the final moment we had with a loved one. Of course, we never expect it’s going to be the last time. And in your case, you certainly didn’t expect it would be the last time.”

My throat feels like it’s filled with acid. “She didn’t make her bed that day, either. I made it for her. And I was mad at her. While she was being killed, I was mad at her. Can you believe that?”

My crying switch flips on. Tears slide down my face.

Dr. Randall nods again. “You’re going to have to learn to let go of your regret, Cora. You can’t hold on to it forever.”

The thing is, though, I’m pretty sure I can. I’m pretty sure I could hold on to it until the end of time.

But hopefully I won’t have to because I’m going to change everything. Quinn and I are going to find that wormhole, and I have a list of the first things I’m going to say to Mabel:

You can always talk to me about anything. I’ll try my best to get it. And if I don’t, I promise I won’t ask too many questions.

Your lip gloss looks cool.

I love you more than anything.

And it’s okay if you never make your bed. I’ll always make your bed as long as it means you’re here.

Those are the things I should have said that morning, but those aren’t the things you say to your sister when you’re mad at her. Those aren’t the things you say until you realize that the world is a place where sisters sometimes don’t come home from school.

It’s going to feel so good to get to say those things to her. I can practically taste the words on my lips.

“You’re smiling,” Dr. Randall says.

I guess I am.

“Are you forgiving yourself, Cora?”

I squirm. I don’t like lying to Dr. Randall. “Forgiveness is, like, an impossible thing, right?”

“I suppose.”

“But it’s also possible. It’s a thing that seems impossible, but it is possible.”

Dr. Randall smiles. He actually smiles. The rareness of it feels like witnessing a solar eclipse. “I like that.”

“Me too,” I say, and spend the rest of the session thinking about how to make an impossible thing—The Impossible Thing—possible.

When our time is up, Dr. Randall rises to his feet and says, “Okay. That’s it for today. I’ll see you next week, Cora.”