The 4½ friends consist of three boys, one girl, and a dog. Kale, the founder and leader of the detective agency "Kale and Company," the twin siblings Steffi and Karsten, Friedel, and their dog, Penta, get involved in various adventures as they attempt to solve mysteries and strange cases.

Kale is thrilled! This year's school festival has a theme of environmental protection, and the best presentation will win a big prize. The event is organized by the teachers, and Kale finds everything very boring. However, if a real case regarding environmental pollution came to their attention...

"Kale and Company" spring into action with the aim of uncovering a real environmental scandal. The team of four friends gets organized, and then they discover something unexpected. Is the ground really polluted? Who is responsible for this destruction?