Peter gets a shock. Jonas learns the truth about his family, but there are more surprises still to come. Helge makes a sacrifice. ...

Ulrich looks to the past for answers and dredges up disturbing family secrets. Armed with new tools, Jonas probes the cave's murky depths. ...

When a grim discovery leaves the police baffled, Ulrich seeks a search warrant for the power plant. A mysterious stranger checks into the hotel. ...