When the building of Primary School No. 17 woke up to life on Monday morning, Room 27 was already bustling with energy - mainly because Kuba, Iga, Michal and Jagoda were sitting inside. These four were not polite children dreaming of a career as class president or diligently learning French. They had much more important things on their minds. Today they were just discussing their latest initiative - the Seventeen Detectives Club. Truth be told, the name was longer than Michael's list of responsibilities at home. But, as Iga put it, if something is to be a real club, it has to have an exciting name. Michal argued that it would be even better if the club had its own uniforms, preferably with capes. Cuba argued that capes were passé, and Berry, as usual, kept them in check before the cape idea turned into an all-day argument. This morning they were in for something special. During breakfast they noticed something very strange. The usher, Mrs Hela, was dragging something huge through the canteen door, wrapped in blue plastic that looked like it had just covered a swimming pool. The mysterious, appetising smell of a mixture of baked bread, ketchup and what Kuba described as a "mayonnaise wind from the south" was spreading through the corridor. - 'Something's up,' whispered Iga, playing the lead role of her favourite character - the super-inspiring detective lady from the show. - 'Maybe there will be burgers for lunch today,' predicted Michael, whose eyes always lit up at the word 'kitchen'. Cuba wasn't going to let up so easily. - I propose an operation: Canteen Surveillance. It's time to see what Hela is hiding under that foil. Before Jagoda could run after her friends, the four of them hid behind an easel in the hallway, which was supposed to display artwork, but happened to be empty - the art teacher had lost the key to the painting cupboard. Michal crawled under the bench and jotted something down nervously in his scrapbook. Iga was looking around through the telephone glass like a thoroughbred spy. Suddenly they heard rustling, then a soft beeping. The canteen door swung open and Chef Franek - a man with a legendary moustache and a talent for making the strangest dishes - looked out. He held in his hands a sheet of paper described in big, bold letters. Cuba only managed to read the first three words before Franek disappeared back: "Giga Sandwich Procedure...". - Giga... what? - hissed Michael, relaying the information like a radio operator. - 'You think this is going to be the world's biggest sandwich? - asked Kuba breathlessly. Jagoda looked at them with seriousness. - 'There's no way we're going to miss something like that! We have to find out what the kitchen is up to. But... At that moment there was a bang, and a blue foil glided slowly across the floor towards a door marked 'ENTRY FORBIDDEN'. The door shook, a strange sound came from behind it - as if someone had dropped ten kilos of tomatoes into a large bucket. The Seventeen Detective Club exchanged glances. A challenge hung in the air. Would anyone dare to go inside and find out what was really going on in the school kitchen? Just at that moment, the headmistress entered the hall. She had an attendance list in her hands and a menacing frown on her brow. She was observing something that the children were never going to find out.... Kuba swallowed his saliva. - Well, I guess it's starting in earnest....