Mia and Benny are two enterprising kids from Hamburg with a passion for investigations. On a trip to the Gruber family farmhouse in southern Tyrol, they discover that the farm has been hit by the Black King's curse.

The peppercorns Mia and Benny are on a school trip in the South Tyrolean mountains. Strange things happen around the idyllic mountain farm where the class is staying: a barn is on fire, spring water turns pitch-black, and the local Luca has the unmistakable feeling that his father's farm is under an eerie curse. The peppercorns, expanded by newcomer Johannes, investigate at full speed. They firmly believe that there is a logical explanation for the incidents and quickly discover that the Hamburg-based food company Levartis has an extremely high interest in the region's water. Luckily, Mia's sister Alice is currently sitting in the peppercorns headquarters in Hamburg and is bored.

Luca Gruber warns Benny's 'peppercorns' bunch, who just outsmarted two thieving bullies, against the school trip to his South Tirol (Italian Alps) home, mentioning a legendary curse of the black king. Bennyis lore concerned about his other as chaperon with and as turns out lover of class teacher Martin Schulze, and the arrival by limousine with Asian driver Hamit of silver spoon class newbie Johannes. The latter proves nosy and clever, eagerly joining their investigation of the 'curse', as scary things happen to Luca's town, including a fire and Luca's father Stefan Gruber's arrest for allegedly dumping hazardous waste. The boy shows his uncle Lorenz the abandoned mine shaft where he thinks the black king haunts, but is locked inside, and Johannes when he comes look for him, so they must escape adventurously, while IT skills help find the real fiends, a food multinational based in their native Hamburg, which must be take on there too, in league with the mayor.—KGF Vissers