Overview: Two children are missing in the huge underground bunkers in Bochum's Westpark, which have long been closed and entry is forbidden. Together with speleologists, the emergency services search through the kilometers of corridors, shafts and halls. Life-threatening dangers lurk here for both the firefighters and the missing children. In another operation, the trainees are initially called to an arbor fire to provide support. But then they are the first unit on site and have to put out their first big fire. There is a danger from gas bottles stored in the arbor.