"Grimm" continues to explore Juliette Silverton's shocking transformation into a hexenbiest. While Nick is still coming to terms with seeing the love of his life become a monster, Juliette is slowly realizing that she is losing her humanity. What more problems could Juliette and Nick face in the upcoming episode?

Episode 18 titled "Mishipeshu" will see Nick and Hank investigate a murder that is interlinked with a dark and mysterious Native American myth. The myth comes to life as the investigation unfolds, reports TVGuide. The duo have certainly come across many supernatural forces in their career, but this may be one of their biggest challenges yet. International Business Times reports that the plot will center on the Native American mythologies of Great Lakes and that the homicide will lead the detective duo on a local Native American power quest.

While the investigation sounds interesting, equally fascinating to watch will be Juliette landing on the wrong side of the law. Fans may recall that Juliette decided to take revenge on Adalind Schade in the last episode. In this week's episode, her quest for the former hexenbiest will trigger her erratic behavior, leading her to have a brush with the law. Will Nick bail her out? How will he react when he learns that the love of his life is in jail?

Back in the spice shop, Rosalee and Monroe embark on a mission but call for Captain Renard's help when they realize they need his assistance. Friday's episode certainly looks fascinating and worth a watch.

Series co-creator James Kouf told TVLine that the season finale has a lot of vengeance. Co-creator David Greenwalt added that the last episode of season four will be filled with revenge and a wild surprise. The report also confirmed that Viktor won't be seen in any forthcoming episodes due to actor Alexis Denisof's unavailability. The actor is busy filming "Finding Carter".

Watch "Mishipeshu" on Friday, April 17 at 8 p.m. ET on NBC.