The radio station at our Julian Tuwim Primary School No. 12 usually sounded like a hoover that had learned to say 'good morning'. Sometimes it crackled, sometimes it whistled, and sometimes, if Mr Leetsky ran his polisher over the cable, it kicked up electricity with sheer awareness. There was nothing romantic or at least a little epic about it - until Monday, when the speakers decided something. My name is Nina. I'm fourteen years old, I run the radio station with Olek, and although this sounds very serious, in practice it means that every other Wednesday I announce doom in the style of: "Attention, flamingo sock found, lonely and vulnerable" and I fight with the volume knob for my life. Olek is half a head taller than me, has hair like Wi-Fi aerials and a knack for finding things in drawers that shouldn't exist, such as cassette tapes labelled "Disco Polonez 1993". Monday seven fifteen, the first lesson was to be maths. The corridor smelled of mop sticks and yellow cheese sandwiches. Olek and I were standing under the notice board when something that sounded like my own throat-automatics grunted from the speaker near the ceiling. - Attention, dear students - spoken by me, that is... well me, but not me. - Please do not lean against the door of Room 214, because in thirty seconds the bag of balls will decide to initiate social life. I looked at Olek. - 'You're the one letting it go? - I whispered. - Me? - he bulged his eyes. - How? We don't even have such a nice word as 'initiate' written down in the computer. Twenty-nine and a half seconds later, the P.E. lady emerged from the staff room with a huge bag that dissolved in a split second like my New Year's resolutions. Balls floated down the corridor in an epic rubber carnival. You could hear squeals, laughter and then "hop, hop, give the balls back", which was about as effective as trying to negotiate with soap bubbles to keep them from bursting. - 'Aha,' said Olek. - 'That was weird. But maybe someone... you know... - he waved his hand, as if trying to fashion a logical explanation out of the gesture. 'I,' meaning the speaker, grunted again. - By the way: class 8B, we do not touch the terrarium in the biology room. The bat that Mrs Niemyska brought in is really sleeping. And no, it's not a "mini turbo bat". - So you can't sell your theory about the rodent superhero anymore - I smeared Olek with my elbow. - The theory was waiting for better times - he replied without offence. After the third announcement, in which my gentle radio tone politely warned the management that 'flowers from the windowsill with pens don't self-pollinate', I started to get hot. Because I didn't record any of these texts. Ba, I hadn't recorded anything since Friday, and if it was a joke, someone had borrowed my voice, ironed it out and put it on like a T-shirt. - Maybe it's a deepfake? - Olek lowered his voice to a whispery conspiracy. - I've seen the film. Seriously, now anyone can sound like someone else. All it takes is fifteen seconds of footage and a clever algorithm. - At our school? - I snorted. - Our radio station computer thinks 'update' is a species of fish. - That's true,' he admitted. - But someone might have brought... equipment. I did something that always ends up funny or stupid in films: I asked. That is to say, during the interval I went to Mrs Mrożek, the director, who has a composed look capable of stopping a scooter in its tracks. - 'Headmistress, can we have a look at the radio room, because... - I started, but Mrs Mrożek raised her hand like a conductor who has just noticed that a triangle has started a solo. - 'Ninotchka, today the radio room is taken care of by the School Sound Club. A pilot project. Mr Łęcki has the key. And no experiments on live air. The School Sound Club sounded like a group that records tombstone podcasts for flowers, but in fact there was a fresh printout on the studio door: 'Please do not disturb - a programme is in progress'. And underneath, someone had written in pen: "from tomorrow". - Someone's in a good mood," Olek murmured. Mr Łęcki was at the door, fumbling with his keys like a maracas. There was a "Sophie" tag on his shirt, but that wasn't his name; that was the name of the floor polisher. Sophie was a lizard in the world of appliances: she had humours and liked to pull shoelaces. - 'Mr Łęcki, we're only here for a second, we want to check what's going on with the speakers,' I asked, putting as much innocence into my smile as a medium-sized rabbit can hold. - 'I'd love to check what's going on with the speakers too, because if it's going on, then the kids are screaming in my ear,' he replied philosophically. - But I won't give the key. Terms and conditions. At this point Sophie, who had been muttering quietly until then, sneezed, slipped on a wet spot and set off to rally through the corridor. Mr Łęcki, without thinking, ran after her. - I'll get Sophie! - he shouted. - Let no one enter the studio! I'm not proud of what I've done. But if someone left the door ajar and clearly wrote 'don't come in', then he simply must have meant 'just for a moment'. At least that's what my brain, which has a built-in translation module of convenience, claimed. - 'We'll go in, we'll look, we'll come out,' said Olek, as convinced as I was. - Zero touching apples with a 'do not touch' sign. We went in. Inside it smelled of dust, tea in glasses with baskets and old vinyl. On a table stood an unassuming audio mixer, a computer with a monitor that glowed like a new moon, and - and this was the strangest thing - a reel-to-reel tape recorder and a cardboard box full of cassettes. Each cassette described in marker: 'Monday, 10:03', 'Monday, 10:17', 'Monday, 10:39'. Today's date. The minutes matched every dash. - Who else uses cassettes? - Olek was surprised. - Probably only dinosaurs and DJs from the 90s. - 'Dinosaurs didn't have tape recorders,' I pointed out. - They lacked cultural overload. I checked my watch. It was 10:36 a.m. My heart was rumbling in my ribs like a tennis ball against a ladder. Olek took the '10:39' cassette out of the cardboard box and raised an eyebrow. - 'It's almost now,' he said. - 'Let's give it a try. If anything, we'll say it's part of the research project 'The echo effect in education'. - 'Echo in education' sounds like the name of a new electronic diary,' I snapped, but my hands were sweaty. We slid the cassette into the tape recorder. The buttons were big, silver and had the kind of shimmer that in movies means 'your finger is about to slip in slow-motion'. Olek looked at me questioningly. I nodded. He pressed PLAY. The tape hummed pleasantly. The hum quickly transformed into something I knew all too well. - Hello, Nino. 'Hi, Olek,' said my voice, as calm as if he were sitting in an armchair with a cat on his lap and a cup of cocoa in his hand. - We are breathing. It's just a sound. I know you have a million questions. The answers will be... some other time. For now, apply a simple rule: don't turn the left knob. - Which left knob? - hissed Olek and retracted his hands as if approaching a pancake pan. - The left one - continued my voice. - If you turn it, the antenna will think it's a propeller and it will fall down. And you don't want to explain to the headmaster why the school suddenly has a helipad. We looked automatically at the panel. The left knob was indeed tempting, as if whispering 'touch me, it'll be funny'. - Okay - I whispered into the speaker, even though it sounds idiotic. - 'We're not spinning. - The second thing - continued my voice from the tape. - 'Someone's going to tap on the glass in a minute. Don't open it. Don't look. Just count to five and.... At the same second, someone lightly taps on the glass of the studio from the corridor side. A short, polite sound. The kind that in normal reality would mean "excuse me, can I have a moment?". It paralysed me, like in a computer game, when suddenly the "Update in progress" window pops up. Olek looked at me, I looked at Olek, both of us at the glass. We didn't see anyone. Knocking again - this time a tad louder. - Count to five - wheezed Olek. - One. Two. Three... - I started, but the tape, as if it knew what number we were on, upped the ante. - Four - said my voice. - Five. Now calmly step back and.... It crackled, as if someone had pressed the pause of the universe. The tape recorder murmured a little higher, as if raising an eyebrow. Another quiet sentence flowed from the speakers, so close to the microphone that I could hear my own breathing. - Don't turn towards the door. The doorknob began to move slowly, with that distinctive metallic click that ends every good break and starts all the trouble. I held my breath. Olek squeezed my glove, though I had no gloves. Someone on the other side of the door pressed harder.