Grimm's 100th episode will spawn a major secret.

'Grimm' Season 5: A 'World Of Trouble' Coming In 100th Episode, Official Summary Unveiled

The NBC drama is gathering speed as it heads for its milestone episode, but once "Into the Schwarzwald" reaches its conclusion, two members of the Scooby Gang will be privy to a little extra information.

"Something big happens during the hour that two characters will keep to themselves for a number of episodes," TV Line teased on Thursday.

'Grimm' Season 5 Spoilers: Nick & Monroe Head Overseas! 'Key Move' Details Are In

So who will be holding tight to secrets following episode 11? The obvious choice would be Nick and Monroe - the two-man team will separate from the rest of the Portland crew when they head to Germany. With the Map of the Seven Knights presumably complete, the Grimm and the Blutbad will be on a treasure hunt in the Black Forest. Will they find something worth hiding?

Back in the States, Hank, Wu, and Renard (Sasha Roiz) will find themselves caught between Black Claw and Hadrian's Wall once more. An assassin will have Portland on its toes, and the cops won't be the only people on the killer's tail. Eve will also have stake in the hunt. Could two of these four stumble upon some integral information?

Find out more when Grimm airs Thursdays at 9 p.m. ET on NBC. Click the video below to see a preview for the series' next episode "Map Of The Seven Knights."

Tags: Grimm television nbc