Team Grimm struggles to interpret the incomplete map from the five (of seven) ancient Keys left by the Grimm Crusaders who buried a mysterious treasure somewhere in the Black Forest. Eventually, they decide that they've figured it out enough for Nick and Monroe to fly out to Germany in the hopes of finding whatever it is before Black Claw can get their hands on in.
Hadrian's Wall warns Team Grimm about the arrival of a Black Claw assassin. Captain Renard, in turn, decides to use the resources of the Portland Police to try and locate the assassin. A pair of bike cops actually do spot him, but the assassin kills one of the cops and escapes.
Nick and Monroe arrive in Germany and begin their search. It doesn't go well; they go to what seems like the oldest church in the area, and it's still too recent. Nick manages to alarm a Mauzhertz and the Blutbad priest with his presence, though, and they gather a mob to track them down. Presumably, they don't want to invite Nick and Monroe to tea.
The two follow the map to a hilltop, where they fall into an underground cavern.
Back in Portland, the assassin makes his move, shooting the mayoral candidate Andrew Dixon.