Monroe hasn't had a very good year, and it's about to get worse.

On Friday's Grimm (9/8c, NBC), after some children died in a mysterious fire that may have been set by a Wesen, Nick (David Giuntoli) turns to an old enemy for help in the investigation. He's not the only one unhappy with the decision though.

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Check out the exclusive sneak peek below to see why Monroe (Silas Weir Mitchell) is about to clean this guy's clock, metaphorically of course.

Grimm airs Friday at 9/8c on NBC before going on hiatus until March 20.