“Grandfather was a historian?” I said. “I thought he was in engineering.”

“He worked in the engine room, helping my mother,” Gran-Gran said. “But his true duty was the stories. I remember sitting in the engine room, listening to the hum of the machinery as he talked, his voice echoing against the metal. But that’s not the story. The story is how we came to Detritus.

“You see, we didn’t start the war—but it found us nonetheless. Our little fleet of five ships and thirty fighters had no choice but to fight back. We didn’t know what the Krell were, even then. We hadn’t been part of the big war, and by that point communication with the planets and space stations was difficult and dangerous. Now, your great-grandmother, my mother, was ship’s engines.”

“You mean she worked the engines,” I said, still sorting beads.

“Yes, but in a way, she was the engines. She could make them travel the stars, one of the few who could. Without her, or someone like her, the Defiant would be stuck at slow speed. The distance between stars is vast, Spensa. And only someone with a specific ability could engage the engines. Something born into us, but something most considered to be very, very dangerous.”

I breathed out, surprised and awed, all at once. “The… defect?”

Gran-Gran leaned in. “They feared us, Spensa, though back then they called it the ‘deviation.’ We were a breed apart, the engineers. We were the first people into space, the brave explorers. The ordinary people always resented that we controlled the powers that let them travel the stars.

“But I told you this story was about me. I remember that day, the day we came to Detritus. I was with my father, in the engineering bay. A vast chamber full of pipes and grids that looks bigger in my memory than it probably was. It smelled of grease and of too-hot metal. But there was a window in a little alcove, which I could look out of and see the stars.

“That day, they surrounded us. The enemy, the Krell. I was terrified, in my little heart, because the ship kept shaking from their fire. We were in chaos. The bridge—I heard from someone shouting—had suffered an explosion. I stood in the alcove, watching the red lances of light, and could hear the stars screaming. A little frightened girl by a bubble of glass.

“The captain called down. He had a loud, angry voice. I was terrified to hear the pain, the panic, in someone who was normally so stern. I remember still, that tone as he screamed at my mother, giving orders. And she disagreed with them.”

I sat there, beads forgotten, rapt. Barely breathing. Why, in all the stories Gran-Gran had told me, had she never given me this one before?

“Well, I suppose you could call it a mutiny,” Gran-Gran continued. “We didn’t use that word. But there was a disagreement. The scientists and the engineers against the command staff and the marines. The thing is, none of them could make the engines work. Only Mother could do that.