Regular readers of Nora Raleigh Baskin will know that the author makes a point of tackling serious, complicated, and difficult topics for her middle-grade audience with singular compassion and humanity. Yet her latest novel, Nine, Ten: A September 11 Story, proved an unexpected challenge. “I’ve had a lot of trauma in my life, personally,” Baskin says, “and I’ve exhausted it in my own writing. But this book was so much harder than I thought it was going to be. It was so much more emotional—and it didn’t happen to me, I didn’t lose anybody. In a way, I really feel like we haven’t really processed 9/11 as a country.”

Nine, Ten follows four children from four very different families, leading vastly disparate lives in far-flung corners of the country. By chance, they all find themselves at Chicago’s O'Hare Airport two days before the attack, and then again at Ground Zero on the one-year anniversary of the tragedy. Aside from those two incidents, they have nothing more in common than the connection that united every American at that time: they lived through a moment when their world was irrevocably changed.

“I don’t remember the world before John F. Kennedy, Bobby Kennedy, and Martin Luther King, Jr. were shot,” Baskin says, “that all happened when I was a little kid. But I do know that I grew up in a world that was really altered by those events. I wanted to write a book about that change—about a time when there was a loss of innocence, a shift in our cultural history. I could have written about any of those, or Pearl Harbor, but I wanted to write one that I actually knew, that I lived through. I wanted to write about a real historical shift, and one that I could remember the before and the after.

“I chose 9/11,” Baskin continues, “because the first thing I remember, at the time, was thinking that the world would really never be the same. And it wasn’t the same, and it was. I remember acutely feeling that I would never feel safe again. But we adjusted. It became the new norm.”

Of the main characters—Sergio, an African-American boy from New York; Aimee, a white, Jewish girl from California; Will, a white boy from rural Pennsylvania; and Naheed, a Muslim girl from Ohio—it was the latter’s experience that Baskin knew needed to be told in particular.

“I was writing a book about the American experience,” Baskin explains of her diverse range of characters, “and I really wanted to show how everyone was affected by 9/11, from so many different backgrounds and communities. Naheed’s character was very deliberate,” she adds, “because I knew that the repercussions of 9/11 were going to affect the Muslim community so greatly. You know, I realized when working on this book that I hadn’t asked my kids about that time. My son, who is in high school, said that kids actually started picking on the one girl who was openly Muslim that day. That shocked me.”

Despite the research required to understand Muslim life in America—her delicate depiction is powerfully highlighted by a scene where Naheed remembers her mother sitting with her in front of a mirror for hours teaching her to wrap her first hijab—it was Will’s story that Baskin struggled with most. When we meet Will, he is still grappling with the loss of his father, who was fatally hit by a car while trying to help someone else who had been hurt in a separate accident, and who ended up dying anyway.

“I wanted to connect Will’s story to Flight 93,” Baskin says. Of course, living in Shanksville, Pennsylvania, where the plane that was intended to hit the White House crashed, he experienced the event and the subsequent flooding of his town with well-wishers, conspiracy theorists, and disaster tourists. But he also experienced something deeper. “The people on that plane, they were heroic, and they died,” Baskin explains. “His dad was trying to save somebody, but he didn’t really save him, but he was a hero just because he tried. How many people actually stand up and try? I really dislike the onlooker, the bystander—people who watch something bad happening and do nothing. In some ways I think it’s even worse, because if you notice someone acting like a jerk, you know better.”

We teach kids to believe in what’s right, to stand up for what’s just. Somewhere down the line, however, as they grow up, so often they forget. They become afraid. At the end of Nine, Ten, the kids stand up to injustice. They say something, and they inspire the adults around them to do the same. “Maybe,” Baskin says softly, “maybe we all need to be a little braver.”

James McDonald is a British-trained historian and a New York–based writer.