Her eyes shine and I know she is trying not to cry and it really bothers me that I feel bad for her. But I do. My dad was her Ben, maybe. And I know exactly how lonely Earth is for her without him.

“You’re right that we did the math all wrong,” Rebecca says. “But I want you to know that your father did take you into the equation— I think you know that a little, since you read the emails. You and Hannah were his whole life. I think part of why he didn’t tell you was because he knew that if you said he had to choose, he would choose you girls. Instantly. Without a thought.” Her lip begins to tremble, and she bites it. “I won’t tell you you’re too young to understand, because you’re not. Love isn’t rational. He and I—your whole family—learned that the hard way. And I will never stop being sorry for the hurt I’ve caused. I can promise you that.”

I look at this woman, and I can’t stop thinking that when my dad looked at her, he loved her. He died loving her.

Mom, help.

When Nah made that funny villain playlist about Dad’s string theory nemesis from Harvard, Mom said something then that I only just now understand: “Our enemies are our best teachers—and sometimes, they become our closest friends.” After Dad died, the nemesis wrote a beautiful article about him in the Harvard Crimson.

I didn’t know how much I’d miss him, the nemesis wrote. I didn’t know he was my friend.

Dad said we can do impossible things, but forgiving Rebecca Chen feels more impossible than being selected as an astronaut candidate.

“Was he happy?” I ask. “With you.”

Her eyes widen a little. And the tears finally spill out. “Yes, Mae. I’m sorry, but yes.”

“And did he know about Pearl?”

Rebecca looks into the stroller, where my little sister is hiding. Her face turns soft. She nods. “We didn’t know we were having a girl, but he said he hoped we would. The last time we talked—the day before the wave—he said he liked the name Pearl. Because—”

“The Three Sisters.”

She smiles. “Yes.”

I think of my dad, floating on the ocean by himself. With all that love in his heart.

“I’m glad he knew,” I say.

Tears fall down Rebecca’s face. “Me, too.”

I don’t know if this is forgiveness, but it’s a start.

There’s a soft gurgling noise from inside the stroller, and Rebecca steps away.

“I think Pearl wants to meet her sisters.” She looks over to where Nah is sitting at the table, not looking at us. “Take all the time you want,” she says, then heads toward a shelf of picture books a few feet away.