“Hang on. I’m only going to bring this up once. I’m not sure I agree with your parents’ decision to send you here for the summer, but I’m not your parents. I know you’d rather be with your friends than with me.”

“That’s not true,” I said unconvincingly.

“I know it doesn’t mean you don’t love me,” Joan said dryly. “But I’m your grandmother, and even though I’m probably the hippest, coolest grandmother there is, I know if I were eighteen years old I would not want to spend my summer being chaperoned by an old lady.”

Her matter-of-fact tone made me ashamed. “I’m sorry,” I said. “I’ve been a jerk about being here.”

“You don’t need to apologize to me. I understand. But you’re here now. I know this isn’t the summer you planned for, but I for one am glad to have the company.”

She spoke lightly, but it reminded me of my conversation with Steph. “You know,” I said, “I was wondering . . .” I trailed off, unsure of how to proceed. I felt as if I were pretending to be a grown-up.

“You can ask me anything,” she said.

“Um, Steph—when I saw her at Safeway—she said she was worried about you. That you’ve been having some trouble with your memory?”

She was clearly surprised. “Oh. Sometimes I forget things, that’s all. I’m getting older. It was thoughtful of her to talk to you about it, but it’s not a big deal.”

“Are you sure?”

“Of course. You don’t need to worry about me.”

“Okay,” I said. The silence between us was a little awkward, and I wondered if I had made a misstep by bringing up Steph’s concern. “So, you want me to take the files downstairs?” I said.

“That would be great. Let me find a box for you to use.”

I went to the filing cabinet and pulled out the rest of the folders. At the back of the drawer, I found a bunch of flat rectangular boxes, each with a photo of Grandpa on the front. He was about my dad’s age or maybe a little older, wearing a blue shirt and a wide paisley tie. Each box contained a videotape titled Understanding Astronomy.

“What are these?” I asked.

Joan came over to take a look. “Oh, Russ did a series of lectures in the nineties for that company that sells them.” She picked up one of the tapes. “Yes. Lifelong Learning. They paid him pretty well, I remember now. It’s basically the survey course he taught at Berkeley.”

I pulled out a bunch of the tapes and looked at them. Each tape contained four lectures, and there were at least a dozen tapes. “That’s a lot of lectures.”

“He was such a good teacher. He loved his research, but I think he loved teaching even more.”