Dominik Mikulaschek (born in Linz in 1983) writes children's books that you start reading "just one chapter" of – and suddenly it's late. He loves puzzles that can actually be solved, rules that can be politely ignored (if necessary) and stories in which friendship is stronger than any clipboard. His adventures are exciting, but never too scary: they're about discovery, about sticking together – and about that tingly feeling when you realise: something's not right here... and we're the first to notice.
Dominik Mikulaschek
Secret passage under the classroom
Children's book for ages 8 and up | Puzzles, school & action
tredition GmbH
© 2026 Dominik Mikulaschek
Printing and distribution on behalf of the author:
tredition GmbH, Heinz–Beusen–Stieg 5, 22926 Ahrensburg, Germany
This work, including all parts thereof, is protected by copyright. The author is responsible for the content. Any use without his consent is prohibited. Publication and distribution are carried out on behalf of the author, who can be reached at: Dominik Mikulaschek, Holzwurmweg 5, 4040 Linz, Austria.
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Chapter 1 – The draught under Milo's chair
As usual, Monday morning at Regelberg Primary School smelled like a mixture of freshly mopped linoleum, old eraser shavings and the firm intention to nip any hint of fun in the bud. Milo Mertens (9) sat in his seat in class 4b and stared at the "sit up straight alarm system" on the wall, which today glowed a particularly suspicious green, as if it were just waiting for someone to bend their spine by a millimetre. Milo tried to keep himself as stiff as a frozen fish stick, but it was difficult when he had the feeling that something was going on under his chair that was definitely not part of the school's official room layout. It started out very small, like the tickle of an invisible feather, but then it turned into a distinct, ice-cold draught that played around Milo's ankles, as if inviting him on an adventure for which there was definitely no form. Milo risked a glance down, which promptly caused the sit-up straight alarm to start flickering nervously in yellow, as if it had detected a secretly crooked soul. Directly under his right foot, the floor suddenly felt... well, different. It was no longer ordinary linoleum stretching like a grey blanket across the entire school, but a place where the air disappeared downwards. Milo moved his foot slightly to the side and felt the cold breath grow stronger, almost as if the school were taking a deep breath. Behind him, a sound suddenly rang out that was almost as forbidden at Regelsberg Primary School as loud laughter during a maths test: a rhythmic knocking. Turbo "Turbo" Tan had decided that the floor needed to undergo intensive material testing today. Turbo was not known for doing things quietly, and so his fist hitting the floor sounded like a small drumbeat in the silence of the classroom. "Hollow!" Turbo whispered so loudly that the whisper meter above the blackboard immediately jumped to orange and displayed a warning for "acoustic pollution". Turbo grinned at Milo as he almost flattened his nose to the floor. "Milo, did you hear that? It sounds like an empty biscuit tin, only without the biscuits and with a lot more echo." Milo nodded frantically and tried to signal Turbo with his eyes to stop immediately before the Office for Peace and Order (ARR) sent a special unit for floor disturbance. But Turbo was already in research mode. He knocked again, this time right next to Milo's chair leg. KLOCK. KLOCK. KLOCK. "Turbo, stop that," hissed Fina Fuchs from the side as she opened her notebook at a speed that almost broke the sound barrier. Fina was the only person Milo knew who could sort dust bunnies by size and trajectory. "If there's a passage, there's a plan," she added, already beginning to sketch the floor tiles, which contained more arrows than a medieval battlefield. She leaned forward and stared at the spot where Milo had felt the draught. "This is not normal wear and tear on the flooring," Fina stated in her logical, factual voice that brooked no contradiction. "The dust particles are moving in a vortex of exactly 12 degrees north-northwest. That means there's a pressure difference here caused by an underground ventilation system or, more likely, a cavity." She energetically ticked off a point on her list that she had just invented: "Phenomenon: Breathing floor identified." Milo felt his curiosity overcome his fear of the sit-up straight alarm. "Do you think there's something down there?" he asked quietly. He thought of the words of caretaker Kratz, who had muttered recently while sweeping the assembly hall that there was often much more to schools than met the eye. Kratz was a man who looked as if he himself were half made up of old building plans and the dust of a hundred years of school history.
That's when it happened: a soft clacking sound came from beneath the floorboard. It wasn't a knock like Turbo's, but a metallic sound, as if someone were turning a heavy key in a lock that hadn't been oiled in a very long time. Milo, Fina and Turbo held their breath at the same time. Even the whisper meter seemed to pause for a moment, as if it didn't know what punishment to impose for underground noises. Milo looked at Fina, whose eyes were now as big as two fully filled O-rings on an ARR form. "Did anyone else hear that?" he whispered. Turbo nodded so vigorously that his hair whipped back and forth like a small storm wind. "That sounded like... like an invitation," Turbo murmured. "Or like someone opening the door to a secret that should have remained locked." Before any of them could investigate further, the classroom door flew open. Mrs Krambeutel entered, her bag making the obligatory CLANG on the floor, and her bun was pulled so tight today that her eyebrows almost touched her hairline. She held a new, bright yellow sign in her hand, which she hung on the board with a determination as if she were proclaiming a new world order. The sign read in black, relentless letters: LESSONS ONLY ABOVE GROUND. Milo stared at the sign and felt his heart skip a beat. Why would anyone make such a rule when there was nothing to discover beneath the classroom? He looked at Fina, who was already writing a new category in her notebook: "Suspicious prohibition signs". Mrs Krambeutel adjusted her glasses and let her gaze wander over the class, lingering at the spot where Milo could still feel the cold draught. "Today we're starting with a special unit on the stability of foundations," she said in a voice as dry as a school sandwich forgotten in a sports bag for three years. "Any knocking, listening or other interest in the subsoil will henceforth be considered a violation of PROJECT UNDERGROUND WAY." Milo froze. Project Underground Way? He had never heard that name before, but it sounded just as bureaucratic and mysterious as everything else Inspector Ordnung and his team from the Office for Peace & Order were planning. He glanced at Turbo, who was trying to discreetly put his head on the floor to catch more echoes. "Turbo, stop that!" Milo's lips formed silently. Fina, on the other hand, was already two steps ahead. She had taken a small dust sample from the suspicious spot and was examining it so intently that she looked as if she could read the secret code to the school administration's safe in it. "This dust isn't from here," she whispered to Milo. "It contains traces of old lime and something that smells like ink from construction plans from 1920. Something has been moved here recently, Milo. Something big." The draught under Milo's chair suddenly became even colder, almost as if someone were pressing against the floor slab from below. Milo could feel the wood give way slightly, just a tiny fraction of a millimetre. It felt as if the school itself was trying to whisper a secret to him, while Mrs Krambeutel was already writing the first paragraphs about the "inadmissibility of hollow fantasies" on the blackboard at the front of the classroom. Milo knew at that moment that this was no ordinary Monday. The signs, the draught and the mysterious Underground Path project all pointed in one direction: downwards. And no matter how many rules Inspector Ordnung laid down, Milo was determined to find out what was really going on beneath his feet. He pressed his hand firmly against the spot on the floor where the cold was coming from and felt a vibrating clacking sound that became more and more rhythmic. A plan was already forming in his head, a real Milo plan that had nothing to do with forms. He looked at Fina, who was already turning to the next page in her notebook, and Turbo, who was licking his finger to check the direction of the draught. They were ready. The secret passage was waiting, and they would be the first to enter it, no matter how many "Above Ground" signs Mrs Krambeutel hung up. Suddenly, the entire floor slab beneath Milo's chair vibrated so violently that his pencil case almost jumped off the table. It was no longer an echo or a coincidence – there was definitely someone or something down there that no longer felt like hiding. Milo held his breath as the light in the classroom flickered briefly, as if the electrical circuit itself were about to give up in excitement. Would the floor hatch open directly beneath them, or was this just the beginning of a much bigger quake? Milo was about to open his mouth to say something when there was a loud crash directly beneath the blackboard, sounding as if someone had dropped a box full of stone slabs. Mrs Krambeutel paused mid-sentence and her piece of chalk broke into two perfect halves. "Chapter two," Milo whispered to his friends as dust from the ceiling trickled quietly onto their notebooks. "Turbo, now you can knock." Milo felt the resistance of the floor lessen, as if the earth beneath them were slowly opening its mouth. Would they fall, or would they take their first step into a world that was never meant for their eyes to see?
Chapter 2 – Turbo knocks on the floor (too often)
