What happened - No one knows

Plot: An unlikely band of misfits has made their home on a roof between a feed mill and the municipal waste treatment plant. But life is good, away from society and living of this leftovers. Lisbeth, Herbert and Walther have created their own self-sufficient little paradise. While Herbert is hunting cats, Lisbeth tends to the self-grown vegetables and Walther angles for usable scrap from the dump down below. One morning though, the peace is disrupted: A nameless, suit wearing stranger has appeared overnight and set up his tent among their huts. He does not speak, but obviously he intents to stay. The rooftop dwellers are anxious. Will he destroy their perfect little society? Or can he be part of it… incorporated so to speak... ?