She set down the soup tureen she had been wrapping in newspaper. “Of course I’ll help. I can’t think of one thing I’d rather do.”

After fixing them both a mug of hot chocolate, she pulled up a chair alongside Nate. He took out the note cards and the library books he and Naomi had been using for their research, and spread the draft pages of their written report, with their dozens of cross-outs and footnotes, across the yellow kitchen table. His mother brought over her typewriter.

“At least there’s one thing I’m still good for,” she said. “I can type like the wind.”

They worked all the rest of that afternoon and into the evening. When they were partway done, Junie came into the kitchen, wanting something to eat. Mom fixed them all sandwiches and set hers down next to the typewriter, so she could keep on working.

All those years Nate had always done school projects with his dad. It had never occurred to him that his mother might be interested. Now she was asking him a million questions, wanting to understand the difference between alpha and beta particles and why it was important to cool the air inside the cloud chamber to just the right temperature.

At eight o’clock they were still hard at work, though his mother took a break to put Junie to bed. “In my day, they didn’t encourage girls to think much about science,” she told him when she returned to the table with a fresh cup of coffee. “When your father used to talk about things like galaxies and stars, I just figured it was beyond me.”

Nate stopped what he was doing and looked at her. “You and Dad are really different types of people,” he said. He had hesitated over the words—whether to say “are” or “were”—but he wasn’t going to talk about his father as if he were dead.

“That’s true.”

“So why did you get together, anyway?” Nate asked her. He was afraid that if he said too much, the moment would end. But he couldn’t let the chance go by without trying to find out some of the answers he’d been waiting for all this time.

His mom took her fingers off the typewriter keys, and for a second he thought she might get up and walk away. But instead, she said, “We were young, for starters. We didn’t know much about what it took for two people to make a life together. But I was crazy about him too. I loved all the wild ideas he used to come up with—exploring caves and building kites and having picnics off in the country.