Grimm season 5 will go on a week's hiatus and return with new episodes on 4 March, at 9pm EST on NBC Network. Episode 11 titled, Key Move, will see Nick Burkhardt and Monroe travel to Germany to search for an ancient treasure aka the Seven Keys.
The official synopsis reads as follows:
Newly gained artefacts are going to take Nick (David Giuntoli) and Monroe (Silas Weir Mitchell) closer to the source of a long-gestating mystery. Elsewhere, Black Claw is going to make a deadly move that will send Portland into disarray.
In the previous episode titled, Map Of The Seven Knights, Nick and Monroe received some Grimm texts sent to them by Uncle Felix, which will also help them get closer to the solution to their Seven Key mystery. The old books had detailed information about Wesens and the Grimm family tree, including Nick.
Monroe also found the secret compartment lock of the trunk, which contained three more keys; combined with the two they had, the gang stamps together the five pieces of the map of the seven knights, ancestors of the Grimm, leading to the Schwarzwald (The Black Forest).
Executive producers Jim Kouf and Norberto Barba shared some details about Grimm's 100th episode titled, Into The Schwarzwald in an interview with Blastr. Kouf revealed that the episode will deal with the keys.
He explained, "When we went to Comic-Con on the first year when we had no idea how long this series would run, we said, 'If we ever get to episode 100, we'll answer the question about the keys,' never thinking we'd actually ever have to answer because what show ever goes to 100? Then when we got to 90 and 91 and 92, we go, 'Uh-oh, we'd better figure out what those keys are'."
"So, I mean, we always had an idea, but now we had to actually do it. But yeah, we're going to deal with the keys in 100," he revealed. And Norberto Barba said that for the 100th episode, "...Nick and Monroe go on a big trip because of the keys, and they find where the keys are. We see what the keys fit and we find out what's in that, and it's mindblowing. It will change things."
So the upcoming episode of Grimm season 5 will be about resolving the mystery of the keys.