Meanwhile, Spider couldn’t settle.

Perhaps he could feel Tom’s anxiety from afar, for he’d been up to the boy’s room several times and stood there, wondering what to do. Phil was downstairs, so he had the run of the house still. He checked the garden and sat in the kitchen, but he felt trapped and uncomfortable. He thought about the little moth and shook himself out from nose to tail: there was no point dwelling on problems he couldn’t solve—and he didn’t want to think about Moonlight. He crept back up to the bedroom, and that was when he heard Phil.

“Spider? Come on, boy…”

He was calling softly in case he woke Tom’s father. Spider could hear him moving about downstairs, and it sounded as if he was in a hurry. The back door opened and closed again, and Spider trotted on to the landing. The front door was open too, and he was about to investigate when he heard Phil pull it quietly closed. There was a scrape of metal, then, as the moped was hauled off its stand. The engine started, and Spider couldn’t believe his good fortune. He listened as the bike puttered away into the distance.

Spider had the run of the house again.

He did a quick tour to check he was really alone. Tom’s dad had his door closed, so he padded past that and went back downstairs. He wasn’t hungry, but it always made sense to see if there was food available, and he could smell the tantalizing scent of digestive biscuits. He found the packet, open in the lounge, and though he knew it was wrong, it was all too easy to reach up and bring them down. It was even easier to crunch and swallow them, and when the sugar exploded in his system he felt a burst of energy that sent him racing back up to the landing. As he did so, he noticed the door to Phil’s room: it was ajar, leaking the usual mix of engine oil and deodorant. Spider had never set a paw over the threshold, and wasn’t quite sure he dared.

He put his nose in and looked around the walls.

Every bit of space was covered in pictures of motorbikes. There were beer bottles and at least half a dozen ashtrays, which made the air rather sour. He was about to retreat when he saw a flicker of movement, like the flaring of a match. It was a bright orange flash, and it came from a bowl in the corner.

“Hello?” said Spider quietly.

The bowl was perfectly round, and full of water. He put his nose to the glass.

“Oh, wow,” said a voice. “How are you?”

It was Hilda the goldfish, and she was swimming in a circle. She was moving slowly, keeping close to the side, and the voice had a bubbly quality: small and friendly.

“Fine,” said Spider. “Thank you.”

“All OK?”

The fish completed a circuit, and bobbed for a moment, staring from wide eyes.

“Good, thanks,” said the dog.

He stepped closer, and the fish set off in the opposite direction.

“How are you?” asked Spider.

“Oh, I’m good too,” said the fish. “Thank you for asking. Quite a day, though, huh?”

“I suppose it is. I haven’t actually been in here before—this is new to me.”

“Really? Why do you say that?”

The fish paused. She flicked her tail and set off on another circuit.

“Because it’s true,” said Spider. “I’m thinking that I ought to go upstairs and wait for Tom. This isn’t my… territory. I mean, Phil seems like a nice person, but I don’t know him as well as I do my master, so I ought not to intrude. I wouldn’t normally be indoors like this.”

“Why do you say that?”

“What?”

“Huh?”

“Why do I say that? Because it’s true. I’m usually in the garden. I’m not sure Tom’s father likes me, and… Well, he makes the rules.”

“Why do you say that?”

Spider paused. “Why do I say what? Which bit?”

“Huh?”

“What?”

“How are you?”

“Look,” said Spider. “I’m fine, but I’m just trying to work things out. I’ve caused a few problems, to be honest. I always worry a bit, because I wasn’t chosen—you know, in the beginning. I was the last dog and they couldn’t sell me, what with this tooth. I’m not much to look at—that’s obvious—so when Tom’s dad saw me, I was given to him. I was a free gift, if you like—I had no value. That doesn’t bother me now, but it’s something I have to remember when I’m thinking about how I fit into the family because, well, the family’s a strange one, when you think about it. There’s something going on that I don’t really get, but I love Tom, and he loves me. I love him to bits, but his dad wanted a cat, which I completely understand. Cats are… very attractive. They’re easy to care for, and they don’t cause the kind of problems I do. Maybe I should try to be more catlike.”

“Hmm,” said the fish. She twirled in a circle and blew a bubble. “Why do you say that?”

“Because it’s true. I know about cats. I know one cat in particular, and I keep thinking about her. She said some very strange things.”

“Huh?”

“She said I might have a cat’s soul.”

“Wow.”

“I know. But what does that actually mean? I can’t work it out, but if she’s right, then I should be with her. You’re a fish, aren’t you, so I don’t suppose you have these problems…”

“Oh, no. You bet.”

“Well, then. If you know what you are, you do what you do. You do fish-things in the same way as I do dog-things. Maybe.”

“Why do you say that?”

“Look, I’m trying to explain… I’m just trying to make sense of it all. Fish swim and eat and… that’s how it should be. I’m looking at you, and I can see that you behave in a fishlike way. What bothers me is that I’m still not totally sure what I am, because—”

“Why do you say that?”

Spider barked with frustration. “I’m explaining!” he cried. “I’m thinking it through! How can we know what we are? I love Tom, but he’s not a dog. He’s human! He throws sticks, and I catch them and bring them back. He’s doing what he does, so I do it too, and we all get along.”

“Why do you say that?”

“Oh, you’re not listening!”

“Huh?”

“This is hopeless—you’re just repeating the same dumb question. I’m talking to a fish—why am I even doing that? You don’t communicate with your owner, do you? Phil, I mean. Does he love you? Maybe he does, in a way. But I sleep at the bottom of Tom’s bed, and in the night if I wake up and feel alone, I realize I’m not. I can feel his heart. I hear it. I’m serious. Just listen—don’t speak. Have you ever found that your heart is beating in the exact same rhythm as someone else’s? That’s what happens with us. Tom smells of me, and I smell of him. But what I’m trying to work out is whether there’s more, and… Oh dear, what if Moonlight is right? Tom might change, and what happens then? Thread, too—I haven’t told you about Thread. It thinks things are going to end badly, so I’m living in a kind of constant fear. Not all the time—I don’t mean that. Most of the time I don’t think—I just get on and live my life, but… you only get one, Hilda. You don’t want to ruin it, and I saw how big the world was. I was on the roof and I saw it, spreading out for miles.”

The fish bulged her eyes slightly, and blew a trail of bubbles.

“It’s so, so big,” said Spider softly. “And you think I’m a mixed-up fool, I know you do.”

“Huh?”

“I’ve got to stop thinking. This is way too deep.”

“Hi.”

“What?”

“Why do you say that?”

Spider howled in anguish, and butted the fishbowl hard with his nose. There was a crack, as loud as a gunshot, and the water slopped out over the table. The dog watched in horror, for the bowl had split and the fish was flicking her tail in alarm. She did two quick circuits, bubbling anxiously. She tried to do a third, but got caught in the weed, which marooned her on a handful of damp gravel. She flopped on to her side, gasping, for the water had run on to the carpet.

“Oh no,” whimpered Spider.

“What?” said the fish quietly.

“I’m so sorry…”

“Why?… Why did you do that?”

Spider gazed at the destruction, feeling more helpless than he’d ever felt. The fish was still opening and closing her mouth, but there were no more words.

Spider fled. He raced downstairs and straight back up again. He rushed into Tom’s room, diving on to the bed and burying himself in the duvet. He was shaking all over, aghast at what he’d done, for the dreadful thing was that there was nothing he could do to put it right. He squirmed back on to the floor and jumped up on to the table. Pens and pencils went skittering in every direction, and he caught one in his mouth and bit hard. Then he was on the floor again, snapping and biting. For five mad minutes he pulled at everything he saw. There was a slipper with a loose sole: it took him ten seconds to rip it apart. There were action figures, and he hurled them into the air. Tom had board games that he never tidied away, and Spider upended them, tearing the boxes. The cuddly dragon came next, and then he attacked a cushion. The air was soon thick with feathers, and the carpet was invisible under a chaos of ripped fabric. There was the felt penguin Tom kept under his pillow. There were the roller skates that stank of leather. There was the golf club, cold against his teeth, and the box of comics that flapped and flew. It soon looked as if the whole room had exploded. The wardrobe was empty of clothes, and Spider was rolling in the mess he’d made. He remembered Moonlight’s magical claws, and tried out his own on a pair of training shoes. He went down low, like a cat and hunted them, and then he returned to the felt penguin, shaking it so hard it fell apart.

By mid-afternoon he’d transformed Tom’s bedroom into a mass of fluff, feathers and ripped-up paper. There were places to roll and tunnel, and, best of all, the whole nest had the intoxicating scent of himself and his master combined. He lay there, panting in relief—and that was when he noticed Thread, dangling just below the skylight.

The spider was smiling.

“My word,” it said. “What a dog.”

Spider stared.

“What a lovely mess you’ve made. Are you happy now?”

“Yes. I think Tom’s going to be surprised, but—”

“Pleased?”

“I think the whole place looks better than it did. Don’t you?” Thread descended, and once again Spider heard its thin, cruel laugh.

“I think he’ll be overwhelmed,” said Thread. “I can’t wait to see his reaction, because you’ve really done it now. For sure.”

He paused, for they could both hear the front door opening, and weary feet in the hall.