“How could he possibly have gotten inside? We’ve been here; we’ve been home.” Mrs. Donahue seemed genuinely confused.

Ben tried to break it to her. “I think that’s what he does, Mom.” She recoiled and stood in the center of the living room, hugging her own body, as if through making herself as small as possible, she could avoid any contact with the Sentry.

“Let’s just stay calm,” I said. “Call the police. We’ll wait for the cops at my house.”

But when I checked my phone, it was useless. At the same time, Mr. Donahue shouted, “I don’t have service!”

Ben waved his arms wildly. He raised his index finger against his lips and then whispered, “McGovern might be jamming service.” He stepped lightly over to the landline and lifted the receiver to his ear. We all waited. Ben shook his head slowly.

Another crash echoed, definitely from upstairs. Mrs. Donahue jumped and then called out, “Ned. Stop this. This is crazy!” Mr. Donahue pointed to the front door and we moved en masse in that direction.

First we noticed the metal glider pushed in front of the door and realized he had been out there, moving stealthily, even as we stood around chatting. Then we smelled the smoke. Lucy craned her neck to see. “The porch is burning. He set the house on fire!” We backed away then, some of us clutching at one another, some of us fighting the urge to scream.

For the first few minutes, it had seemed like just another mystery. Where was Ned McGovern? What would the Sentry shake up next? But at that moment I saw a look pass between Mr. and Mrs. Donahue—terror.

Mr. Donahue led us back to the kitchen. We moved as one entity, facing different directions in case Ned broke through a wall and we needed to fight him off. We felt the heat against the back door even before we saw the flames. “Dad? Windows?” Ben asked in a quick, low voice.

Mr. Donahue clutched his head, trying to think. “Double locks. We added all this extra security.” He sounded apologetic.

Ben spoke directly to me. “We’ll use one of the passages. All that racket, he won’t expect us to go upstairs.”

I shook my head. “It will take too much time for everyone to climb down. And that might have been the clanking sound. We could get up there and find that he somehow destroyed the whole ladder.”

“Smart,” Ben said. One word. And my chest felt warm not because the house was on fire but because I impressed a boy.

Together we shepherded everyone the few steps to the cellar. “Livvie and I have a plan,” he whispered. “You have to trust us.” Ben turned the knob and the door stuck. He furrowed his brow as he rammed his shoulder against the wood. It opened with a muffled thud. Ben met my eyes and glanced up. I knew what he was thinking—the sound was enough to have clued in the Sentry.

We hustled everyone down the steps. Ben led up front and I took the back, twisting my neck, half expecting McGovern to burst through the basement door. I heard the exact moment Ben opened up the refrigerator.

“You want me to do what?” his father asked.

“You have to trust us,” I hissed. “Ben knows what he’s doing. He’ll go first and lead you through. I’ll be behind you.”

“Yeah?” Ben asked, over the heads of his family.

“Yeah.” I motioned to the fridge. “Go.” He hoisted himself up, crouched low, and crawled through.

I got to work tying back the refrigerator door. For a second, I debated it. If I tied the rope to the anchor hook, it would tip off the Sentry for sure. But if I let the door close behind me, we had no way back. We didn’t know yet if the path was clear.

I knotted the rope. One by one, we all scrambled up and through. Mr. Donahue tried switching places with me, but I nudged him forward. I whispered, “I know what to do.”

Crawling through the gritty tunnel, I felt hot and sweaty and tried not to let my imagination get away from me. I wondered if the house above us was already burning. In front of us, Ben called out a constant stream of reassurances. “Low here. Watch your head. Almost there. Keep moving.” He kept his tone just as upbeat, just as steady when he said, “Hey, Ned. What’s going on?”

Mr. Donahue and I hadn’t reached the end of the crawl space. He stopped short in front of me. “Go back,” he whispered.

“No way.”

“Olivia, right now,” Mr. Donahue ordered. Then he pushed forward to be with his family. If I crawled back, I’d be crouched down in the hot tunnel, listening to something terrible happen. I knew that. Stuck in that long coffin of darkness and dust, witnessing, with a fire behind me.

So I pushed forward. When I reached the wine cellar, I found that Ned had everyone sitting with their backs pressed to the stone wall. He stood over the group waving two long pieces of metal. One was a set of lawn shears. One was an ax. As Ned spoke, he gestured with the tools. They made the shadow he cast on the wall look like a monster with claws.

I stayed in the tunnel, hopefully unseen. Ned was already ranting.

“You have no idea what you have done. What you have trampled on. This was a sacred place. This was a place of joy. You came in here with your complaints and your petty disagreements and had the nerve to be ungrateful. I kept waiting. I thought maybe you just needed a reminder. How did you manage to live in this kind of splendor and still be so unworthy? Langsom property for generations. And I was no Langsom. I was never allowed to forget that. I was a visitor—a charity case. And then the mighty fell, didn’t they? Suddenly there was a window of opportunity.” I watched a vein in Ned’s temple pulse with the rhythm of his anger. “I just needed a few more months to get together the down payment.”

“So you did write the letters to drive us out?” Lucy piped up. Obviously, there was no one she was reluctant to antagonize.

“I wrote the letters to warn you.”

“Don’t be ridiculous!” Lucy cried out. With every word, she seemed just as undone as Ned. “Warn us about what? Your hidden collection of scout badges? The commission you earned from the sale brought you closer to the down payment. That must have been so frustrating—like some sad real estate O. Henry story. But if you handled the resale, you’d double your commission. And who would want to buy the notorious Sentry house? You would do us a favor, taking the property off our hands. Except Dad got a little overzealous and added you to the lawsuit. That complicated the situation. Otherwise, everyone would be calling it the McGovern house, wouldn’t they?”

Ned’s grip tightened around the ax in his hand. I saw his knuckles whiten. “It will always be the Langsom house. And I was always looking in. Even from the inside, I was still looking in.” He scoffed. “You’re no different. Do you really think they call it the Donahue house? When they talk about it tomorrow, they’ll say, ‘Did you hear about the Langsom house? It burst into flames.’ ”

With that, he stretched his arm and went after the pipe above their heads with the ax. I didn’t know what it was at first, but saw the look of horror wash over Mr. Donahue’s face. And then, one by one, the rest of us seemed to realize the danger. Janie dove first. She clawed at his arm and bit his shoulder and even stomped on his knee. After Janie broke the spell, the whole mob of us tackled McGovern while he flailed with his sharp blades against the gas line.

A fire raged above us. And Ned McGovern raged too. He was so strong. He kept tossing Mr. Donahue off him like he was a dog shaking off drops of water. And then he would swing his arm and the shears would arc through the air, the blades almost whistling. Every time the head of the ax clanged against the pipe, we expected the air to explode. “Get out!” Mr. Donahue screamed to the rest of us.

Ben bent toward his dad and pointed at the passage to the yard. Mr. Donahue shook his head.

Ben pointed and yelled, “The gas valve. By the shed.” He dove for Ned’s waist and held him back. “Now!” Ben screamed. But Ned wasn’t chasing us anymore. His blank stare had focused completely on the pipe as he swung and swung at it.

Mr. Donahue crouched with his arms over his head and ran forward as if the ceiling was already on fire. Mrs. Donahue guided Janie and Lucy out and yelled at me to follow. I couldn’t hear outside myself. I might have only screamed Ben’s name inside my head.

But probably not. Because for a split second right before Mrs. Donahue yanked me forward, Ben looked at me and said calmly, “I know what to do.” And then he let go of Ned McGovern and stepped backward into the opposite tunnel, the one leading back to 16 Olcott.

Mrs. Donahue was boosting me up when we heard the explosion. It sounded like the noise when they launch fireworks, right before the sky lights up. That deep thunderous sound of igniting. We felt a fierce gust at our back. It pitched Mrs. Donahue forward, smacking her head against the hinges of the trapdoor. Sprawled on the ground, I felt myself trembling everywhere but then realized it was the earth shaking beneath me. Janie and Lucy knelt down and together we hauled Mrs. Donahue out of the hole.

“Gavin?” Mrs. Donahue asked desperately.

“I got it.” Mr. Donahue had reached the valve and almost tore off the handle in his panic. We collapsed in a pile—all of us—entwined and weeping beside the old wood shed. We shielded our eyes against the thick smoke and stared at 16 Olcott, expecting it to fall. And then the night filled with sirens and the red lights of fire trucks.

In the middle of all that chaos, Mrs. Donahue asked, “Where is Ben?”

In answer, Mr. Donahue scrambled to his feet, trying to run back inside. We all screamed then. He didn’t get far before needing to turn around. Thick plumes of smoke streamed from the passage, blocking any entry.

When the firemen found us, they moved us farther back, to the edges of the property. They examined Janie’s arm and Mrs. Donahue’s forehead. They kept shining a penlight into Lucy’s eyes and she kept swatting it away, staring at the scorched ground like she expected someone to crawl out. One of the firefighters spoke into his radio. “Various degrees of shock. One case requiring stitches.” My parents were with us too. With me. Asking me questions. But I could only look at the house.

Then I saw him walking toward us, a firefighter on either side.

Ben was covered in dark soot, except for light streaks around his face where he’d wiped away sweat or tears. His hair stuck out wildly and his clothes were frayed. “Hey, guys,” he called out as if it were any ordinary Saturday night and he’d shown up late for dinner again. “There goes the neighborhood.”

I know for certain that I didn’t shriek his name out loud that time. I left that to Lucy and Janie, who knocked him to the ground with their hugs, quickly followed by their parents. The firemen looked over and grinned. One of the firemen stepped forward. “Mr. and Mrs. Donahue, I don’t know who taught this young man to shut off the internal gas valve in an emergency, but that was time well spent. Your boy’s actions saved your home, possibly lives up and down the street.” Their dad reached down to squeeze Ben’s shoulder and their mom wiped away tears.

The fireman nodded and gave a moment before he continued. “Now we’ve resolved the small fires at the front and back of the main domicile, with minimal damage to the building. Obviously there are structural issues that will take weeks and months to address. I would recommend that you spend tonight in a neighbor’s home or a hotel.” He cleared his throat. “Because of the history of the property and your most recent conversations with law enforcement, we do have some questions. We would like to conduct interviews tonight.”

“Absolutely.” Mr. Donahue nodded. “As soon as my family checks out medically, you understand.”

“Of course.” The firemen looked at each other. “Your son did indicate this was a deliberate act. Of course this is a small town in terms of news. We’re familiar with the letters you’ve been receiving.”

“A sick man, Ned McGovern.” Mr. Donahue looked away. “Particularly shocking because he was a friend of the Langsom family.”

“Well, I’m sorry to say the team hasn’t found anyone else inside. That root cellar in your backyard is, for all intents and purposes, incinerated. We’ll get down there as soon as we can. Heck of a shame.”

My father spoke up then. “Ned McGovern. Someone should inform his wife.”