With his multifunctional desk, Peter Lustig takes up residence wherever questions about nature and the environment arise: sometimes in the forest, sometimes in a lignite mine, sometimes in a hydroelectric power plant. Unlike in the series "Löwenzahn", the program "mittendrin" is not only devoted to environmental topics from the children's area, but also explains problems of ecology with which they actually have nothing to do. In a clear and easy-to-understand way, Peter Lustig explains the greenhouse effect and what could be done about it, or how crude oil is extracted and used.