Make no mistake: the May 21 season finale of Grimm is going to be epic. And even though we’ll see encouraging moments of “romance” between Nick (David Giuntoli) and Juliette (Bitsie Tulloch), the episode takes a pretty dark/crazy turn. ”One of the main characters dies at the end,” David told HollywoodLife.com and other reporters May 13 at the NBC Upfront in NYC. But wait, there’s a catch!

David specified that someone “dies,” and yes, he used air quotes.

“I don’t want to lead you astray,” he said. “But one of us kind of dies and may or may not be coming back. We’ll see.”

(All I can say is, it better not be Wu!)

Royally Screwed

The whole ‘Royal Family’ subplot has been a little scattered this season, but David assured us everything will come together on the finale.

“The Royals are going to come to Portland in a big way,” he said. “Nick will be in peril more than he’s ever been in peril. The Royals introduce us to a level-10 Vessen guy.”

David was, of course, referring to Baron Samedi, played by the “wonderful” Reg E. Cathey.

Mommy (And Scheduling) Issues

Nick’s mom has been M.I.A. since the beginning of season two — actress Mary Elizabeth Mastrantonio‘s schedule hasn’t allowed for a return — but David said we might not have seen the last of her.

“There will be references [to Kelly],” David said. “There will be communiqués. I’m not sure in what capacity she’ll be back next season, but I’ve been hearing things.”

(Fingers crossed for a family reunion!)

WATCH: ‘Grimm’ Season Finale Promo

HollywoodLifers, how do you hope the Grimm finale ends? Who will ‘die’? And will Nick and Juliette finally get their happy ending? Drop a comment with your theories and predictions below!

— Andy Swift
Follow @AndySwift

More ‘Grimm’ On HollywoodLife.com:

1. ‘Grimm’ Guest Star Reveals Personal Connection To Halloween Episode
2. ‘Grimm’ Scoop: Reggie Lee Promises Sex, Fights & Shocking Discoveries
3. ‘Grimm’ Video: What’s Next For Hank’s ‘Season Of Discovery?’

Every episode of Grimm is borderline terrifying, but tonight’s Halloween-themed hour is especially so — and for guest star Kate del Castillo, the episode’s all-too-real villain “La Llorona” holds a special place in her nightmares. “Every single Mexicana has heard [the legend of] La Llorona,” Kate tells HollywoodLife.com of the Mexican folktale featured in the episode. ”It would scare the hell out of us!”

For those of you who aren’t properly educated in South American folklore, La Llorona is the ghost of a beautiful woman who killed her children to be with the man she loved — and as if that wasn’t tragic enough, the man still wouldn’t be with her. Now the spirit is said to be wandering the earth, seeking little children to snatch up. And that’s where Kate’s character, Valentina Espinosa, comes in.

“She’s a detective from New Mexico who’s obsessed with La Llorona because she lost her nephew,” Kate explains. “He was kidnapped under her watch, so for her, it became an obsession. That’s why she goes to Portland, to help the detectives find her. She knows the case.”

Juliette (Bitsie Tulloch) even gets to play translator and show of her Spanish-speaking skills, which Kate says are very impressive: “She did amazing!”

Kate’s appearance on Grimm is also meaningful to her as a Latina actress, because the episode will air in Spanish on Telemundo immediately after it airs on NBC. Kate recently starred on the Telemundo miniseries La Reina Del Sur.

“I’m their guinea pig,” Kate says. “Well, not me, but the episode. I think it’s genius! It’s time, and it couldn’t be better than with this episode, which is so Mexican. I’m honored and happy to be the one broadcasted by NBC and Telemundo for the first time.”

As an added bonus, we also have behind-the-scenes photos from the episode of Monroe (Silas Weir Mitchell) and his “haunted” house! (Oh, did you expect him to not be obsessed with Halloween?)

Grimm‘s Halloween episode airs at 9 p.m. tonight on NBC!

— Andy Swift

Follow @AndySwift

More Grimm on HollywoodLife.com:

1. ‘Grimm’ Video: What’s Next For Hank’s ‘Season Of Discovery?’
2. ‘Grimm’ Season 2 Video: Can Nick Handle His Mom AND Save Juliette?

While most of your favorite shows won’t be back with new episodes for more than a month, NBC’s Grimm is getting a jump on the fall schedule by launching its second season Aug. 13 — which is good, because Nick Burkhardt (Dave Giuntoli) definitely has an extra month’s worth of drama on his plate.

Not only is Nick still reeling from the surprise return of his presumed-dead mother Kelly (Mary Elizabeth Mastrantonio), but he’s also racing against the clock to wake Juliette (Bitsie Tulloch) from her cat scratch-induced coma.

Watch a special behind-the-scenes preview of Grimm‘s second season below:

And if you’re lost — which is understandable, given the ridiculousness of it all — watch this special 7-minute recap of season one:

— Andy Swift

Follow @AndySwift