Santa stood in the hallway of his school. The uniform was too tight and rustling. Monday's assembly smelled of floor polish and extinguished hopes. Suddenly he heard a whisper from under his left pocket: "Ouch, don't pull!". He looked around. No one was looking. The headmaster was just tweaking his moustache, and the emblem hung crookedly. "Is that my stomach?" - he thought. Whispered again, "Hello, I'm a button. And don't play with the thread, it tickles." Nikolai twitched so that Zuzka from the parallel class poked him in the elbow. "Stop talking to the flapper or you'll get called out!" - she hissed. "But it's the flapper who's talking to me!" - he whispered. The button moved slightly and made a proud grunting sound. "Do I have a name? No. I'm Button. I know all the secrets of this school because I've been carried everywhere." Nikolai swallowed his saliva and pretended to cough. "Pretend you're laughing at the headmaster's joke," - advised Button. The headmaster was just telling his annual number about the electronic diary, sounding like a broken bell. After lessons, Nikolai hid with Zuzka in the empty common room. "Can you hear him?" - he asked. "I don't, but I can see that your klatch is alive." - she snorted. Button grunted gravely. "I need help. The school bell sounds like a dachshund coughing. I know how to fix it and make the mischief of the century. It's called Operation Kwak." Zuzka lit up immediately. "If it's legal in another galaxy, I'm all for it." Button buzzed a thread. "Mr Wozny leaves the keys in the thermos. There's a panel from the speakers in the basement. There's also a security seam that opens a passage under the chemistry room." It sounded absurdly like a competition for the best mine. And that's why it smelled of adventure. Before the evening chess circle, they snuck out into the corridor. The lights buzzed and the clatter of cups came from the staff rooms. Button pointed with a thread to the wall by the cup display case. "Here. Turn me twice to the right, once to the left." Nikolai grabbed the button and made a move. Something inside clicked and the slat near the floor moved away on his finger. A whiff of dust and cold came from inside, like a fridge full of riddles. Then the characteristic grunt of the director and the clanking of keys carried down the corridor. Zuzka's phone vibrated: "Dyra's coming!". Button's voice tightened. "It's now or never. Three full turns and the panel will slide out." Nikolai tightened his fingers on the button, heard someone's footsteps around the corner and