I knew I was in big trouble. My teacher, Mrs. Henderson, had said if I was late one more time, she would call my parents. And there I was, running as fast as my eight-year-old legs could carry me, my backpack slamming against my back.

The morning sun was already beating down hard on the sidewalk of Oakwood, our little town in Ohio. I could feel sweat trickling down my neck. I had spent way too many minutes searching for my lucky baseball cap that morning, and now I was paying the price.

My name is Ethan Miller, and I’m a second grader at Oakwood Elementary. My parents, Susan and Robert Miller, both work really hard, and they trust me to walk to school on my own. I’m a big kid now, or at least I tell myself that. But right then, I felt small and scared.

Mrs. Henderson’s voice from the day before kept echoing in my head. “Ethan, this is your final warning. I do not tolerate tardiness. If you walk through that door late again, I will telephone your mother and father immediately, and we will have a very serious talk.” The way she said it, with her glasses perched on the end of her nose and her finger pointed right at me, made my stomach twist.

I decided to cut across the FreshMart grocery store parking lot. It was a shortcut I’d taken a hundred times, past the big green sign and the rows of parked cars. Usually, there were a few early shoppers, but that day the lot looked almost empty, except for a few scattered vehicles baking under the sun.

As I raced past a silver sedan, I heard it. A faint, muffled cry that stopped me in my tracks. At first, I thought maybe it was a cat or some bird, but then I heard it again—a tiny, weak whimper. A baby’s cry.

I pressed my face against the car window, cupping my hands around my eyes to see inside. My heart nearly leaped out of my chest. There, strapped tightly into a car seat, was a baby girl. Her cheeks were bright red and wet with tears. Her little forehead glistened with sweat, and her mouth was open, but the cries were getting softer, like she was running out of energy.

I froze for a second, my mind racing. Where was her mom? Why would anyone leave a baby alone in a locked car? I looked around frantically. The parking lot was still empty. No one was walking out of the store. No carts were clattering. It was just me and that baby.

I tried the driver’s door handle. Locked. I ran around to the passenger side. Locked. I pulled with both hands, but it wouldn’t budge. The back doors were the same. I even checked the trunk, just in case, but it was no use. The car was completely sealed up.

Through the glass, I could see the baby’s tiny chest rising and falling fast, and her skin looked so flushed. My dad had always warned me to never stay inside a parked car on a hot day. He said it could get dangerous in no time. I felt panic rise in my throat like a big lump.

I thought about running to the school to get help. But it was still a few blocks away, and by the time I came back with a grownup, it could be too late. The store wasn’t open yet either. The sign said it opened at nine, and my watch said it was only 8:35.

I looked down at my own trembling hands and tried to think. Then I saw a rock near the curb, half buried in the dried mud. It was about the size of both my fists together, rough and gray. A terrible idea popped into my head.

I knew if I broke that window, I’d be in the worst trouble of my life. I remembered Mrs. Henderson saying she’d call my parents. She might even get the police involved. I could see my dad’s disappointed face and my mom crying. But then I looked at the baby again. Her cry was just a tiny squeak now.

I couldn’t let her die. The thought burned in my brain like a fire. I couldn’t just walk away and pretend I didn’t see anything. I had to do something, even if it meant I’d be punished forever.

I picked up the rock. It was heavier than I expected, and my skinny arms strained as I lifted it above my head. I remember my whole body shaking. “I’m sorry, Mister Car,” I whispered out loud, my voice cracking. “But I have to save the baby.”

I slammed the rock against the side window. A loud crack shot through