My brother is a superhero, and I am my brother.

Somewhere on the way back from a parallel Earth, Zack and I had swapped bodies. My eleven-year-old mind was in his fourteen-year-old body, and vice versa. I shuddered at the thought. I didn’t even like wearing his hand-me-down trousers, so to think that I was in his actual skin? Yeuch.

I stared at him – me – across the floor of the tree house. I’d never seen myself like this before – mirrors don’t tell you the truth, and my Evil Twin had better hair. (Side-note: lots of people have cousins who live in a different part of the country; I have a superpowered twin in another dimension. Also, a cousin in Birmingham). I looked myself up and down. My Spider-Man T-shirt was as amazing on me as expected, but I didn’t appear as tall as I’d hoped and I was definitely on the skinny side. Moreover, at that moment my face was pinched with concern, but I put that down to Zack.

He was frowning at Zorbon the Decider, representative of the High Council of Frodax Wonthreen Rrr’n’fargh, mysterious bestower of superpowers, and the garishly purple-costumed alien who’d landed us in this body-swap horror story. We’d travelled home from another universe together on his interdimensional bus earlier that afternoon. During the course of the journey, Zorbon had shrunk from the height of a basketball player to something approaching R2-D2 proportions. He explained that crossing dimensions could do strange things. No kidding.

As Zack glowered and Zorbon gave his best all-knowing expression, I realised for the first time that the unfortunate situation had thrown up one very interesting consequence. In all the fuss it had almost slipped me by. If I was Zack, then that meant…

“I have superpowers!”

I heard my brother let out a long groan. He could complain all he liked. I had more important matters to attend to: I was desperate to try out my new-found abilities. First I’d go with a bit of telekinesis, then maybe I’d telepathically sneak into Dad’s head and discover his secret Christmas-present hiding place, after that definitely some flying—

“They’re not yours,” Zack snapped. “They’re mine.”

“You didn’t even want them in the first place,” I reminded him. “They’re in the right hands now. Technically they’re still your hands, but I’m in control.” I wiggled my fingers to demonstrate.

“Well, we’ve all seen what happens when you get powers.”

He was referring to Stellar, my Evil Twin. And yes, it was true that he had made some questionable decisions while using his powers, but that didn’t mean I would.

“Just don’t muck about with them,” Zack added despairingly.

“Should I even pretend I’m going to pay attention to that?”

I had superpowers. Finally! Sure, it wasn’t exactly the way I’d hoped. Along with telekinesis, telepathy, flight and the rest, I had gained terrible dress sense and a one-sided longing for my neighbour’s big sister. But still, I was in the body of a superhero. My greatest dream had become a reality. When Zorbon first visited the tree house I had missed out on becoming Star Lad and my world was thrown into confusion. Today, the natural order of things had been restored.

I aimed my telekinetic power at a comic lying on the floor of the tree house and concentrated. “Up, up, up,” I mumbled. But the comic didn’t move. I didn’t give it a second thought. A minor teething problem at most.

What I needed was a mission. Something to test my new abilities.

That was Zorbon’s department. From what Zack had told me of their meetings, whenever Zorbon visited he always left a hot, spicy clue to what lay in store. Kind of like a trans-dimensional pizza delivery guy. Usually Zorbon hung around just long enough to tease this world-shattering threat before scarpering. But today Zack wasn’t giving him a chance to get the slightest mystic prophecy into the conversation.

“Can’t you do something?” Zack pleaded, his voice – my voice – rising to a squeak of horror. “You must be able to change us back.”

“THAT IS BEYOND MY POWER,” Zorbon said. “HOWEVER, THE EFFECT IS TEMPORARY. YOU WILL RETURN TO YOUR OWN BODIES. IN TIME.”

“But when exactly?” Zack asked.

“HARD TO SAY,” said Zorbon.

“Try,” Zack insisted.

Maybe this was the mission. Body swaps happened a lot in comics. There were rules. “Presumably there’s some sort of fabled object we can go on a quest for that will reverse the effect. Y’know, a mysterious old lamp, an ancient stone, a fuzzy sweater?” The other two looked at me. “A magically imbued fuzzy sweater, of course.”

Zorbon shook his head gravely. Well, that was a poor show – what kind of curse didn’t have a fabled object to undo its effects? But just when it seemed as if the outlook was all doom and gloom, Zorbon raised one thin eyebrow.

“SOME SAY A REVERSE MAY BE TRIGGERED THROUGH STILLNESS AND SILENCE.”

Zack tutted at me in disgust. “No chance then. You can’t sit still for two minutes and you can’t keep your mouth shut for two seconds.”

Hanging out with my Evil Twin I’d got used to being insulted by myself, so I didn’t rise to the bait. It was clear that, for now at least, we were stuck this way. I looked out across the garden towards the house, where Mum and Dad were busy inside. I may have been craving an implacable foe, but there were already two in the kitchen. (“Implacable” means cold-hearted and ruthless, and is not, as my friend Lara believes, a word to describe teeth resistant to cavities.)

“What are we going to tell them?” I muttered.

The last time they’d seen either of us was during a rampage by a world-eating monster in the town centre at the weekend. I’d had to give them the slip, ducking out of a rescue helicopter during the emergency evacuation. By my reckoning that had been two days ago.

I felt Zack at my side. “They must be going out of their minds with worry.”

This would be the second time we’d returned home following a cataclysmic event, armed with a flimsy explanation for our absence. Once our parents got over their relief that we hadn’t been squished beneath a giant interdimensional sandal, they were bound to grow suspicious. And there’s only so many times you can play the I-got-bumped-on-the-head-and-suffered-temporary-amnesia card.

“THEY ARE NOT CONCERNED ABOUT YOU. AT LEAST, NO MORE THAN USUAL.”

“How do you know that?” asked Zack.

I narrowed my eyes in suspicion at Zorbon. “Yeah, what have you done?”

“I MERELY SUBSTITUTED THEIR—”

“Minds? Memories?”

“TEABAGS.”

“Come again?”

“IN YOUR LANGUAGE IT IS CALLED THE INFUSION OF OBLIVION. THEY WILL REMEMBER THE EVENTS OF THE LAST FEW DAYS BUT NOT YOUR ROLE IN THEM.”

“You drugged them?” Zack was outraged.

I was not so offended. A drink that made your parents forget what you’d done? Yowzah! “Got any spare?”

“THERE IS ONE MORE THING.” Zorbon pulled himself to his full height, which currently lay somewhere around my belly button. “IT IS VITAL THAT YOU PAY HEED TO MY NEXT WORDS.”

The air crackled with anticipation. Here it came – Zorbon the Decider’s Big Mystic Message. Would his latest forecast be up there with “Nemesis is coming”? We were about to find out.

“DO NOT LET THEM OPERATE HEAVY MACHINERY FOR TWENTY-FOUR HOURS.”

As far as uncanny prophecies went that was something of a let-down.

“Is that it?” I asked, not trying to conceal my disappointment. “What about the giant space lizards?”

Zorbon’s bald head creased with puzzlement. “I DID NOT MENTION ANY GIANT SPACE LIZARDS.”

“Exactly,” I said. “Where’s my Evil Horde? Army of the Undead? Come on, I’ve got superpowers now – I need a supervillain to battle.”

“Well, I don’t,” Zack sighed. “All I seem to do lately is avert one apocalypse after another. Honestly, I’d love a break from saving the world.”

I started to complain but it was no use. Zorbon wouldn’t be dropping another hair-raising adventure in our laps this time. After clarifying that he would also not be dishing out free samples of the Infusion of Oblivion, he announced his departure. He had to be on the other side of the universe by supper-time. With a swish of his purple cape he swept out. He may not have been leaving us with a mission but he could answer one thing for me.

“Keeping busy then?” I asked him.

Zorbon paused, one foot already out of the door. “YES.”

“Lot of Deciding to do, I imagine.”

“LOTS.” He turned to me. “I FEEL THE WEIGHT OF YOUR UNASKED QUESTION, LIKE A REFRIGERATOR IN THE WIND.”

He was right. Weird, but right. I’d been burning to ask him this particular question since we were introduced on board the 227 bus on the way back from my Evil Twin’s world. I didn’t waste any more time. “Here’s the thing. Zack was a mistake, right?”

“Hey!” my brother objected.

“What I mean is, when you showed up here that first time to give out superpowers, you meant to choose me. Didn’t you?”

Zorbon’s frame filled the lower half of the doorway. A gust of wind caught his tea-towel-sized cape and it flapped around his shoulders. He gazed up at me, the stars on his chest pulsing. “ONE DAY, LUKE PARKER, YOU WILL COME TO UNDERSTAND.” Without uttering another word he turned on his tiny heel...