I couldn’t wait for school to be over. That was true most days, but today more than ever, because I wanted to rush home and work on my idea. I didn’t even care that Julianne would be there.

I tried really hard to listen to Mr. Peary, but by the end of the day the margins of my notes were full of scribbled ideas. Luckily he didn’t call on me and catch me daydreaming this time.

Finally the last bell rang. I nudged Danny and leaned over to include Eric, too. “You guys want to come over and help me with something?” I said.

“Yeah, totally,” Danny said.

We found Troy outside, waiting with his little sister. When his mom pulled up, he talked her into letting him come with us. She gave him the same speech about being home for dinner and not leaving my house. As soon as she pulled away with Eden, the four of us started running.

We raced all the way back to my house. Of course Danny won, but I wasn’t very far behind. I could see Merlin watching out the window for us. That gave me an extra burst of speed at the end. When he saw us come around the corner, he started barking and barking. It was funny, because I couldn’t hear him through the glass, but I could see his mouth moving and his ears flapping back.

Julianne opened the back door as we came through the gate into the yard. Merlin flew across the grass toward me. He leaped and danced and spun in circles, woofing and pawing at me. Julianne laughed.

“Hey buddy,” I said, dropping to my knees and rumpling Merlin’s fur. “I know, I missed you, too! Did you have a good day?”

“I hope so,” Julianne said as if I’d been talking to her. “We watched a lot of TV, I’m afraid. But we played out here for a while, too. He headed for the fence a couple of times, but I was able to distract him with the tennis ball or the Frisbee, thank goodness. I had visions of chasing him down the street all the way to your school! But you were a good boy, weren’t you, Merlin? As long as I played with you, you figured you’d stick around.”

I was glad Merlin hadn’t showed up at school. But I was also jealous. I didn’t want Julianne to be a good enough substitute for me in Merlin’s mind. She was already trying to replace Camellia. I wouldn’t let her replace me, too.

Eric kicked my ankle surreptitiously. He nodded at Julianne.

“Oh,” I said. “Yeah, um, thanks. Thanks for hanging out with him.”

“No problem — it was fun,” she said with a huge smile.

Then Danny kicked my other ankle and raised his eyebrows.

“By the way,” I said, rolling my eyes at him, “this is Danny. And Eric and Troy. Guys, this is Julianne.” They all said hi.

She beamed at all of us like I’d just invited her into our secret clubhouse or something. “Nice to meet you guys!” she said. “Lucky Merlin, to have so many friends. Well, I’d better be going.”

“Going?” I echoed. I nearly said, “You’re not staying for dinner?” but I stopped myself in time. I didn’t want to sound like I was inviting her to do that.

“Yeah, I’m trying to clean up my portfolio for this gallery in New York,” she said. “Doesn’t that sound ridiculous? I feel like such an art snob talking about portfolios and galleries. But it’s just this little place. It’s a long shot. Anyway, we’ll see. So I should go.”

“OK, ’bye,” I said.

“ ’Bye,” Troy and Eric said at the same time.

“Good luck with your portfolio!” Danny said warmly. She smiled again and I felt a little bad that I hadn’t even thought to say something like that. Too bad Danny and I couldn’t trade places. He’d probably be much nicer to his dad’s girlfriend than I could be.

As soon as she was gone, I explained my idea to the guys and we started searching through the garage. I was sure there was something in here we could use. Merlin stayed close to me, poking his nose into every box. This time I remembered to hide Camellia’s stuffed animals from him before he found them.

Troy found the first thing we needed. It was still attached to Camellia’s old bike. My dad had bought it for her when she first started riding around the neighborhood by herself. He was really nervous that something might happen to her. It was soon after Mom left, and Dad was dealing with us by himself. He was afraid of cars and everything else on the road.

So he bought her the loudest bike horn in the history of the world.

Troy squeezed the black rubber bulb at one end. The horn went BWAAAAAAAMP! Even though we were looking at him when he did it, all of us jumped a mile — including Merlin. Perfect!

Danny helped me move things away from the back wall until we found the pile of scrap wood my dad has been gathering for years and years. He has a new plan for it every summer. Maybe he’ll build a deck! Or a treehouse! Or a sawhorse. Sometimes he even buys a book on woodworking and stares at it for a few days before giving up. But he keeps adding to the pile of wood “just in case.” Whenever he sees a piece of scrap wood by the side of the road, he brings it home. Camellia loves to tease him about it.

And now we were finally finding a use for it! Well, some of it. Just one piece, actually. One long, narrow piece of wood.

I grabbed the roll of string from the workbench and we dragged the piece of wood out to the fence. Merlin trotted along beside us, sniffing the wood curiously. He tried to get his teeth around it, but we took it away from him.

Inside the yard, he ran in big circles while we stood by the fence, trying to rig up my genius device. It was really lucky there were four of us. Danny and Eric each took one end. They held it up level with the top rail of the fence, only a couple of inches away from it. I stuck the rubber bulb of the bike horn between the wood and the rail. We moved and fiddled and tweaked everything until the wood was just far enough from the rail to hold up the horn without making the noise go off. Then Troy ran along the fence, tying the wood to the fence rail at exactly that distance.

When he was done, we carefully … carefully … let go.

The long bar of wood stayed in place. The bike horn was trapped between it and the fence rail. And hopefully — if this worked — putting any pressure on the wood would make the horn go off. Like, say, if you hit it with your front paws.

This was only part one of my plan, though. Part two was convincing Merlin that I would come back, every time. I ran inside and got his bag of treats. I locked the door as I came out, as if we were really leaving. Merlin was flabbergasted. He dropped the tennis ball and stared at me in disbelief. How can you be leaving already? he seemed to be thinking. We haven’t even played at all!

At the fence we had to do some crazy maneuvering to get under the board and out through the gate without letting Merlin out. But we managed to make it to the other side with my device still intact. I wrapped the bike chain through the links, but I didn’t lock it. I had a feeling Merlin would go for jumping the fence every time now that he thought it was easier than opening the gate.

He trotted back and forth along the fence, watching me.

“ ’Bye, Merlin!” I said. “We’ll be right back!”

Troy ran around the hedge into our neighbor’s yard, in case Merlin did get over the fence and made a run for it. Danny climbed his tree again so he could watch what Merlin did. Eric came with me. We waved to Merlin and walked away down the street.

We weren’t even halfway down the block when we heard BWAAAAAAAAAMP! I turned around, half afraid that Merlin would be running up behind me. But there was no sign of him.

“Let’s wait a sec,” I said, stopping out of sight of the house.

“This is a pretty cool idea,” Eric said. “Houdini would totally have done something like this. I mean, if he had a dog like yours. You know he designed a lot of the trick boxes he worked with?”

“That’s cool. I hope this works,” I said. We started walking back to the house.

Merlin was sitting on the other side of the fence, looking up at the bike horn. When he saw us he leaped to his paws and barked excitedly. His tail whisked back and forth. He crouched and made a jump for the top of the fence.

His paws hit the wooden board. They pressed it back toward the fence. The bike horn was squeezed between the wood and the fence rail.

BWAAAAAAAAAAAAMP!

Startled, Merlin lost his momentum and fell back to the ground. He shook himself and looked around with this hilarious bewildered expression. I waited another minute until he was calm again. He sat back down and looked at me, tilting his head.

“Hey buddy,” I said, coming up to the gate. I crouched to get to eye level with him. “See? I came back.” I fed him a treat through the chain links. “Good boy. Good stay.”

“That was the funniest thing I ever saw!” Danny called down from the tree. “The look on his face! When the horn went off the first time — it was like a squirrel had just landed on his head. He had no idea what it was, but it made him get away from the fence really fast. Ha!” Danny started laughing again.

I said good-bye to Merlin again while Troy and Eric traded places. Troy and I headed down the block. Again we heard BWAAAAAAAAAAAMP! behind us.

We stopped and waited. Silence.

“I wish we could get a dog,” Troy said wistfully. “Maybe a bloodhound, like the kind that help the police find missing people and solve crimes and stuff.”

“Then he could come over and play with Merlin,” I said. “That’d be awesome. You know, whenever he’s not out solving mysteries.”

We headed back and the same thing happened again. When Merlin saw us, he went bonkers. He barked and jumped and spun and then he tried to leap up to jump over the fence. But as soon as his paws hit the board, BWAAAAAAAAMP! He fell back, shook himself, and stood there looking startled.

Again I waited until he was calm, and then I went up and fed him another treat. “Good boy,” I said. “And here I am again. Just like I promised.”

Merlin wagged his tail.

“You guys don’t have to stick around for this,” I said to my friends. “I bet it’s super-boring for you. I just have to keep doing this until he stops trying to get out.”

“I want to stay,” Troy said.

“Me too,” said Eric.

“Me too, as long as we go to the park eventually,” Danny said with a grin.

I grinned back. Julianne was right about one thing. Merlin and I were lucky to have friends like these.