After a month-long hiatus, NBC's "Grimm" will finally return this Friday with a new episode that promises to be intense as Nick copes with the reality that his girlfriend, Juliette, has been transformed into a Hexenbiest.

As fans may recall, in the last episode of "Grimm," Juliette confessed to Nick that she has turned into his mortal enemy, leaving him in complete and utter shock. The upcoming episode, titled "Bad Luck," will pick up right where the last installment left off.

In a recent interview with Entertainment Weekly, "Grimm" star David Giuntoli opened up about his character, Nick Burkhardt, the future of Nick and Juliette's relationship and the final episodes of the season, which he says will change Nick's life forever.

Giuntoli described Juliette's transition into a Hexenbiest as a really bad "side effect" and compared it to "the worst STD a person can get." He added that although Nick "feels terrible" about Juliette's condition, he "is definitely going to try to work it out with her," said the actor. "Whether she can work it out with Nick is another story. But Nick's going to try to figure out a way to make it all work."

The actor also teased the case of the week, which will focus on a man whose foot has been cut off and the superstition of the lucky rabbit's foot. Meanwhile, Rosalee and Monroe will go undercover to help solve it.

"It's very macabre," said Giuntoli about the episode. "We have creatures in the world that are actually wesen, human, creature, wesen-oids. And when you saw a foot off a live rabbit ... it's a bad scene. Our writers are taking it to a dismal, dark, horrible place."

In addition, Giuntoli dropped spoilers about the last episodes of the season, which will feature Nick's mother and the return of Trubel.

"You get to see Nick's mom, you get to see Trubel, and things change in Nick's life that'll never be the same. I'd say the events that take place in Nick's life, in probably the last five episodes, are as momentous as him finding out that he's a Grimm. These are the biggest cliffhangers we will have ever had on the show, and there's going to be about three of them," he said,

According to TV Guide, the official teaser synopsis for "Bad Luck" reads as follows:

"Nick and Hank investigate the murder of a man who was found with his foot cut off, apparently as part of some Wesen ritual for good luck. But in order to find the culprit, Monroe and Rosalee need to go undercover. Meanwhile, Nick's still reeling from the fallout of Adalind and Juliette's showdown, and he ends up on a path to Henrietta."

"Grimm" Season 4, Episode 14, "Bad Luck," airs on Friday, March 20, at 8 p.m. EST on NBC.

Watch previews below.