On the corner of Sparrows Street stood the strangest shop in all of Little Pines. A sign hung above the door: The Mistake Shop - Enter at your own risk and with a sense of humour. In the shop window blinked merrily clocks that refused to indicate Monday, and between them swayed an umbrella that only opened in the sun with an obstinacy worthy of a cactus. Lila and Maks came here every day after school because the Mistake Shop belonged to their Aunt Kaja, a person who could fix anything, provided it wasn't fixed too perfectly. Aunt Kaja wore purple glasses, a flowery apron and hair pinned up as if she had a pencil hidden in it (which was usually true). She stacked all sorts of inventions on her shelves: socks, which always got lost in pairs, buttons, which occasionally laughed, and notebooks, which themselves added endings to essays, although they usually ended with: "And then everyone went for pancakes". - 'Rules,' Aunt Kaja would remind us as soon as the children crossed the threshold. - Firstly, we don't touch anything without asking. Secondly, if we do touch, we don't start an apocalypse. Thirdly, once the apocalypse starts, we call for me. On that June afternoon, a crowd of customers was getting ready: the music lady wanted a metronome that counts to three and a half, the postman was looking out for a bag that carries itself, and the gentleman from the vegetable shop was dreaming of a cucumber that learns to walk to the fridge. Lila (eleven years old, an eye for detail and pockets full of paper clips) and Maks (ten years old, a hundred questions a minute and the ability to eat crackers without making a sound) stood behind the counter and sorted colourful warning cards. Outside the window, a delivery truck braked with a screeching murmur. The driver, all decked out in "Do not shake!", "Do not turn upside down!" and "Do not sniff if you have already sniffed" stickers, pulled a large box out of the cab. It was covered in checkered tape and had so much writing on it that Lila felt the alphabet begin to spiral inside her. - Delivery for the Mistake Shop. Signature and any apologies,' the driver muttered, handed over a pen and disappeared before her aunt could count to two and three-quarters. The box landed on the counter with a groan that sounded like a hiccup. Then... hiccup again. And again, so loudly that the jumping alarm clock fell off the shelf and stopped jumping from the sensation. - 'Oho,' said Aunt Kaja, glancing at the children from over her glasses. - 'I was going to unpack this after closing time, but the music lady is about to start paying me in quarters. Take a preliminary inventory. Just remember the rules. - We don't touch anything without asking," Lila repeated. - And we don't start the apocalypse - added Maks proudly. - 'And when we do...' began Aunty, but the bell above the door rang like a church bell, and the umbrella from the sun tried to open over the customer's head. - Oh, I'm off to save Mr Stefan's haircut. Children, watch out for... The sentence disappeared under a wave of boisterous pleasantries. Lila and Maks were left with a box that had just made a sound like "hik!". - 'This box is lurching,' Maks stated, putting his ear to it. - Does this mean that something inside has swallowed air? Because if so, should we give it back to him? - First we read the labels - decided Lila, because labels were her favourite part of life. She nodded. - "Do not shake," she said. "If shaken, see point one." "Do not open on an empty stomach." "Do not open after overeating". "Do not open when it is raining". "Do not open when the sun is shining". - So only open when it's twilight and slightly hungry? - guessed Maks and giggled to himself. - There is also a sticker: "Voice activation. Tell a joke you don't know". - How can I tell a joke I don't know? - outraged Lila. - It's like asking for a surprise that you wrote yourself. Pointless. The box responded with another hiccup, and confetti popped out of one crevice - one, pink, with dots - and landed awkwardly on Max's nose. - Aaaa-psik! - sneezed Maks. - This box sneezed at me! Is that legal? Lila looked around the shop. Everywhere was teeming with things that couldn't wait to do the wrong thing. The fan yawned protractedly. The ruler made a quiet announcement: "Attention, I'm cutting my lunch break short." As always in the Mistake Shop, it was warm, colourful and a bit like someone had mistaken a film set for a dresser. - Maybe there's something inside that needs to be fed a joke," Lila contemplated. - Only the jokes I know are all well-known. And here it says unknown. - I can invent a new one! - rejoiced Maks. - Listen: Why did the circulator walk away with the maths in unison? Because he had a lot of angles in him to work on himself! The box did the 'hick' with such enthusiasm that it moved on the tabletop. The pyramid of cups trembled, and the umbrella with the sun at the top turned offended to the wall. After a moment, the box made a quiet, very careful sound, as if someone were trying to clap a glove. - 'I think that's applause,' whispered Lila. - Or a clap. Is oklap also applause, just tired? - 'Maybe it's a test,' said Maks, who liked tests as long as they didn't result in a grade. - Let's do what they say. We've got a joke that no one's heard before. Next... is there any more instruction? Lila found a yellow card taped to the corner: "Caution: content may take offence to Częstochowa rhymes". - Phew, we're lucky,' gasped Maks. - My joke was about the angle... ah, never mind. - I said: stay away from rhymes - replied Lila. - OK, tests passed. What's next? The box moved its lid so gently you'd think a unicorn with bamboo hooves lived inside. For a second, less than half the crunch of a cracker, the smell of... lemon kissel escaped the box. Or maybe pancakes? Either way, the smell was sweet and a touch of the birthday table. - Did you hear that? - a porcelain salt shaker in the shape of a cat winked at them. - Oops, sorry, I shouldn't say. - You shouldn't, but we appreciate it - Lila nodded to the salt shaker. - Maks, gloves! Maks knew where to look. From under the counter he pulled out a pair of hippo-shaped oven mitts. The Mistake Shop had the best gloves for silly and unknowable things - cool on the inside, funny on the outside. Lila slipped her hands in and rested her fingers on the lid. - Wait! - hissed Maks. - Rules! Do not start the apocalypse! - It's just a box - whispered Lila. - Besides, if the apocalypse, we have an auntie. And after the apocalypse - pancakes. From the corner came the voices of customers: the music lady was trying to stroke a metronome that wanted to be adopted by a turtle, and Mr Stefan was arguing with his umbrella about whether the sun had the right to shine in his hat. Aunt Kaja juggled screwdrivers like a professional juggler and called out again and again: "I'll be right back to you!" in a tone that usually meant "I'll come back and bring lemonade". The box vibrated again. This time very clearly. A quiet, tentative knock sounded from inside. One. Two. Three. Lila looked at Maks. Maks looked at Lila. The fan stopped yawning. Even the salt shaker pretended to be just salt. - Hello? - Maks said, very politely, into the box. - Can anyone hear us? For a moment there was a silence so thick it could be sliced and served with tea. Then the box... burst into laughter. A real one, short and a little creaky. - 'Okay, now I'm scared,' Maks admitted, but his eyes lit up as if someone had fired two tiny bedside lamps into them. - 'We're opening on three,' said Lila. - Once... The box beeped, as if it was afraid of odd numbers. - Two... A paper spider flew down from the ceiling and kindly handed Lilka a thread, 'just in case'. - Three. Lila lifted the lid with her hippo gloves. Something inside purred like a very small engine, flared with a lemony glow and then they heard a clear, distinct whisper coming from the box: - Who tells the first joke? Lila exchanged a quick glance with Maks. The lid lifted a centimetre, then two, and the air became like a fizzy drink - bubbling and tickling the nose. Over the very edge, just beneath their fingers, something trembled... and before they could take a breath, the box did something that no indulgent box in the world does - it lightly, but firmly, pushed the lid towards them and