115 degrees. That is the exact number the digital dash in my sedan flashed at me when I pulled into the gravel drive last July, and it is the number that still wakes me up at night when the house gets too quiet. Clara was six months old then, just starting to babble, with round cheeks that stayed flushed pink no matter how many times I stripped her down to her cloth diaper.

When the central air gave out on a Tuesday afternoon, I didn’t panic right away.

Appliances break in the desert. You call the landlord, you wait out the worst of the afternoon, you deal with it. But when I dialed Gary, our property manager, his voicemail picked up with that cheerful automated chirp that makes you want to throw your phone through the drywall.

By Wednesday morning, the indoor thermometer read 98 degrees. By Wednesday night, it hit 104 inside the living room. Clara wouldn’t nurse. She just lay across my chest, too hot to cry properly, letting out these tiny, dry whimpers that sounded like a cat stuck behind a wall.

I called Gary again. This time he picked up after four rings, his voice thick with the sound of a television playing in the background. He told me he had a crew coming out next Tuesday. Next Tuesday. A week away.

“She’s six months old,” I told him, and my voice cracked in a way that embarrassed me. “Gary, it’s over a hundred inside. She’s turning red.”

“Not my emergency,” he said. “Put a fan on her.” And he hung up.

I called the city housing authority next, sitting on the sticky linoleum of the kitchen floor with sweat dripping off my chin onto my knees. A woman with a flat, tired voice told me code enforcement required landlords to provide habitable conditions, but they had a backlog of forty-two calls ahead of mine. She said she would send someone out by the end of the week. No one ever came.

By Thursday afternoon, the apartment felt like the inside of an oven left on the self-cleaning cycle. I filled ziplock bags with ice cubes from the freezer, which was barely holding its temperature, and wrapped them in dish towels, wedging them around Clara’s crib while she slept in short, restless bursts. I sat on the floor beside her with a battery-operated desk fan blowing warm air across my face, crying so hard my nose bled onto my shirt.

That was when I needed air. Not just cool air, but any air that didn’t feel like breathing through a wool blanket.

I pushed the front door open and stumbled out onto the concrete porch. The heat hit me like an open furnace door, stealing the breath right out of my lungs. I sat down on the top step, burying my face in my hands, wondering if I should pack us into the car and just drive toward Flagstaff until we found a motel with working refrigeration.

“Your AC broke?”

The voice was thin and raspy, coming from a few feet to my left. I looked up and squinted against the glare bouncing off the asphalt.

Mr. Davis was standing at the edge of his property line. He lived in the unit directly attached to mine, a mirror image of my small two-bedroom, but his side had heavy wooden blinds pulled tight against the sun year-round.

He was seventy years old, maybe seventy-five, with thinning white hair that stuck to his forehead and a pair of khaki work trousers that looked three sizes too big for his shrunken frame. I had lived next to him for eight months, and our only interactions had been a polite nod when we took the trash bins out on Thursday mornings.

“Yes,” I managed to croak out, my throat dry as sandpaper. “Landlord isn’t coming until next Tuesday.”

He didn’t say anything for a long moment. He just stood there under the blinding sun, his pale blue eyes blinking slowly behind thick glasses, looking at the screen door behind me where Clara’s faint whimper had started up again.

“Give me twenty minutes,” he said.

He didn’t wait for an answer. He turned around, his joints stiff, and shuffled down the concrete path toward his side gate. I heard the metal screech of his garage door being yanked upward, followed by the heavy clatter of things being moved around in the dark.

Twenty minutes later, he came back around the corner. He wasn’t wearing a shirt now, just an undershirt grayed by years of wash cycles, and his thin shoulders were slick with sweat. He was dragging an ancient, heavy window unit behind him. It was a metal box the size of a small suitcase, painted a faded almond color, with rusted louvers and a thick yellowed power cord trailing in the dirt like a dead snake.

“Mr. Davis, you don’t have to, ” I started, standing up and swaying slightly from the heat.

“Hush,” he said, and his voice had a sudden, hard authority that shut me up instantly. “Go inside. Open the bedroom window.”

I scrambled back into the apartment, desperate enough to accept help from a stranger. I unscrewed the old wooden slats of the bedroom window, pushing the glass up until it jammed. A minute later, Mr. Davis appeared outside with the unit resting against his chest. His hands were shaking visibly, the blue veins in his forearms standing out like ropes under his skin.

He hoisted the heavy metal box onto the sill. It slipped once, scraping a patch of skin off his knuckle against the aluminum frame, and a drop of dark blood hit the sill. He didn’t even flinch. He jammed a folded wedge of cardboard under one corner to level it, shoved the side panels out, and jammed the plug into the outlet beside the bed.

The machine let out a sound like a lawnmower starting in a tin shed. For three terrifying seconds, nothing happened except the lights in the bedroom dimming. Then the compressor kicked in with a deep, shuddering groan, and a blast of air so cold it smelled like rusted iron and winter poured out of the plastic vents.

I stood there in the middle of the bedroom and let the cold air hit my face, and my knees just gave out. I sat right down on the carpeted floor and started laughing and crying at the same time, listening to Clara’s cries fade into a soft, even sigh as the temperature in the room dropped thirty degrees in ten minutes.

When I finally crawled back out to the porch, Mr. Davis was sitting on an overturned plastic bucket by his gate, wiping his face with a greasy shop rag.

I pulled my wallet out of my back pocket with trembling fingers. I had seventy-four dollars in cash from grocery money. I held it out toward him.

“Please,” I said. “Please take this. I know it’s not enough for the unit, but, “

He didn’t look at the money. He kept his eyes fixed on the dirt between his work boots, his thumb tracing a dark stain on the rag.

“Put that away,” he said softly.

“Mr. Davis, you can’t just give me your air conditioner. How are you going to stay cool?”

“I was in the army,” he said, and the words came out flat, reciting something he hadn’t spoken out loud in forty years. “Korea. Cold winters, hot summers. You learn how to sweat.”

He paused, and the silence stretched out so long I thought he was going to get up and walk away. But he didn’t. He looked up at my window, listening to the steady, rhythmic roar of the old machine keeping my baby alive.

“I had a daughter once,” he said, and his voice dropped an octave, the raspy edge smoothing out into something hollow. “She died when she was two. Summer of seventy-two. AC went out just like yours did. No money to fix it then. I would have done anything to keep her cool. Anything in this world.”

He looked back at me then, and his eyes weren’t old anymore; they were just tired, carrying a weight I couldn’t even reach.

“Take the unit,” he said. “It’s yours.”

That was the last time he spoke about her.

Over the next few months, after the landlord finally sent a crew and our central air was restored, I tried to return the window unit. I knocked on Mr. Davis’s door with a casserole dish in my hands, but he shook his head before I could even finish the sentence. He left it sitting in my garage, wedged between a box of old college textbooks and a stack of plastic storage bins.

By winter, the old compressor finally seized up for good when I plugged it in just to test it. A smart person would have hauled it to the curb for the metal scrap man. But I didn’t.

Instead, I started checking in on him. At first, it was just dropping off a plate of lasagna on Sundays or asking if he needed milk when I ran to the market. He was gruff at first, standing in his half-lit doorway with the screen door hooked, taking the plate with a short nod. But slowly, over the autumn and into the mild desert winter, the gap narrowed.

By spring, he was letting me step inside to sit at his Formica kitchen table while he drank instant coffee from a chipped mug with the handle glued back on. His house smelled like old paper, peppermint tea, and pine cleaner. One afternoon while he was out in the garage, I noticed an old wooden bureau in the hallway with a small, square frame resting on top.

I didn’t mean to look, but the glass caught the light. It was a black-and-white photograph of a young soldier in an ill-fitting uniform holding a little girl with dark curls who looked almost exactly like Clara did at six months old. Tucked neatly into the bottom corner of the frame, behind the glass, was a tiny, faded pink leather toddler shoe with the sole worn flat at the toe.

Mr. Davis walked in behind me, holding a wrench, and I froze, feeling like an intruder in a museum of a life that had ended decades ago.

“Her name was Lily,” he said quietly, his voice lacking any anger, just a heavy, settling finality.

He didn’t yell at me to get out. He just walked past me, set the wrench on the counter, and poured a second cup of coffee, setting it across from the empty chair where I stood.

“Sit down,” he said. “I’ll tell you about her if you want.”

And he did. He talked about her laugh, about how she hated the crusts on her toast, about the way she used to pull on his dog tags when he came home from the motor pool. He talked for two hours, clearing out a space in his mind that had been locked up tight since 1972, letting the words out into the room like someone opening a window after a very long fire.

Now, Clara is two years old. She runs around the living room with plastic toys clattering against the tile, her dark curls bouncing just like the little girl in the photograph.

Mr. Davis doesn’t walk as well as he used to. Some afternoons I see him sitting on his porch, staring out at the asphalt where the heat waves shimmer off the hoods of parked cars, looking smaller and more fragile inside his khaki trousers than he did last year.

I don’t leave him alone much anymore. When I make dinner, I set a plate for him and bring it over while it’s still hot. Sometimes we sit on the front steps together as the sun dips behind the mountains and the desert air finally starts to cool down, watching Clara chase lizards across the gravel.

And back in the dim, shadowed corner of my garage, sitting right where it has been since that terrible Tuesday last July, is the rusted, almond-colored window unit. It doesn’t hum anymore. It will never blow cold air again. But every time I walk past it to grab the stroller or the garden hose, I rest my hand against its cold, heavy metal casing, feeling the ghost of a summer that could have ended so differently, and I whisper a thank you to the man who gave away his only comfort to keep my baby alive.